What's this loud tapping sound from my new engine?

[robroy]

Good evening!

For your amusement, I picked up one of Tom's business cards during my last visit; here it is:

Front:



Back:



It's a really nice business card that my scanner didn't do justice to!

I need to find a builder like this Tom guy but deals with 429/460s near me.

I'm not sure about the near you part, but Tom does indeed do 429/460 engines. I asked him about this during my first visit, and heard that he really specializes in Ford engines. Although I gather that FE engines are his "pet," he has built plenty of 429/460 engines also, it seems.

Thanks for all the outstanding guidance!
Robroy

[robroy]

And now for some information on the new build!

After explaining my desired characteristics for the vehicle (my application) in detail, the main theme I heard from Tom was that I'll be happiest with an engine that's primarily built for torque. I heard that torque at low RPMs is what's going to get the truck moving for street driving, and for driving in the mountains (up steep hills where I keep having to slow down for corners, then immediately speed up again).

He recounted the way he configured his 1970 F250 Camper Special (428/C6) for torque and how well it did (on the street, while towing heavy trailers, and even once on the track)!

It's ideal to work with an engine guy who likes (and has experience with) Bumpsides. He can relate to exactly what I'm building.

Updated notes on the build:

1. Using the 428-sized pistons, the engine will have 406 CID.
2. Tom would like to build the engine with 9.7:1 compression. He likes this ratio because there's a little room for carbon build up before the compression gets so high that detonation becomes a real problem (on high octane pump gas).
3. I asked Tom about what main upgrade came to mind, if I were going to spend a little more cash than his initial build idea. Tom said the #1 upgrade would be a roller camshaft and lifters! That adds around $700 to the total price, but as I understand it, will prevent the same type of camshaft failure the engine already suffered. I also heard that the engine will produce more torque with this roller camshaft and lifter setup.
4. Based on Tom's advice, we agreed that I'd go with a Crower roller camshaft (I forget which brand he recommended for the lifters, but naturally they'd be selected to match the camshaft).
5. With low RPM torque in mind, Tom recommended selecting a Crower grind that will result in a mild "muscle car" type of idle at around 650 RPM. Note that the previous camshaft setup required a 900 RPM idle.
6. I heard from Tom that unlike their flat tappet camshafts, the Comp Cams roller camshafts are OK. Despite this, since I'd heard good things specifically about the Crower parts Tom said he'd stick to those.
7. ARP head bolts will be used. The engine already had ARP connecting rod bolts, so those can probably be re-used.
8. With regard to accessory bolts, I declined Tom's offer to use ARP bolts for those too, since they're more of a cosmetic item there (I'm guessing). Do you think I made the right choice?
9. I asked Tom about stroker kits. He said that although it would increase the performance potential a lot, it would also add an extra $2,000 on to the price tag for the engine. And considering the type of performance he thinks he'll be able to build in to this engine with the standard 390 crankshaft, I heard that it probably wouldn't be worth it (in my case) for the cost involved. This said, I did hear that beyond the roller camshaft and lifters, the stroker kit would be his next suggested upgrade.
10. I asked Tom about the Edelbrock aluminum heads. Tom explained that he recommends those heads primarily for high horsepower applications (for light vehicles), because the increased flow through the ports can decrease exhaust temperatures and velocity, which can be torque-robbing. Tom went on to explain that he'll port my existing iron heads, and that removing material from the top side of the ports is more effective for building torque than removing from the bottom side.
11. Tom mentioned that the new engine should have a 160 degree thermostat, and will like to run between 165 and 170 degrees.

Tom entered some numbers in to his Dyno 2000 software and provided me with these printouts. Although the numbers aren't finalized yet, this shows the performance and temperament ballpark.

Before showing me these numbers, Tom explained that although software dyno numbers can be very misleading, these particular ones should be fairly close. To support this, he showed me the comparison between the Dyno 2000 output for his Mustang engine and the actual dyno output, and they matched within just a few horsepower all through the RPM range! It was really impressive.











I should see if Tom will scan a copy of the draft invoice he wrote for me, so I can post that here too. It's detailed and itemized.

For the moment, I asked Tom to pause activity on the engine until I'd discussed its parts and specs here for a short while. Maybe y'all (there it goes again) will have some advice for me on this!

Thanks very much for the truly excellent help!
Robroy

[iamthewreckingcrew]

500 ft lbs of torque will get ya moving for sure. I'm not even sure my 460 is making that kind of power.

[DuckRyder]

"rods numbered, but not to the hole they were in"

that seems to support some of our previous speculation.

Edit, - Oh:

Who are the CSI folks?

TV show - Crime Scene Investigation - you know, Marge Helenberger, Jorga Fox...

I've got some more thoughts I'll post later...

[Ranchero50]

One quick question is it worth redoing the heads you have vs. getting another set from a yard and redoing them?

It sounds like you have a good build coming along, 500ftlbs at 2k is going to move you well, it's almost naturally aspirated diesel territory. Probably a good 2.5" mandrel bent exhaust with a 2" H in the pipes and it should be over 500 at 2500rpm. The compression looks good, should be interesting to see how it runs when done.

Funny, when I was looking for the bad from PU I saw where a guy on the vintage mustang forums was looking at them for a 302 based motor and was turned to Keith Craft instead and got a really nicew motor for around $6-7k.

Jamie

PS, when it's in are you going to run it up to Tom and let him tweak it a bit or at least check it out?

[robroy]

Good morning IAmTheWreckingCrew, Robert, and Jamie, thanks for your great replies!

500 ft lbs of torque will get ya moving for sure. I'm not even sure my 460 is making that kind of power.

Excellent! Yeah that's a very solid amount to generate at such low RPM, isn't it?

"rods numbered, but not to the hole they were in"

that seems to support some of our previous speculation.

Edit, - Oh:

Excellent analysis! I see what you mean about the speculation and Tom's comments fitting together so well.

TV show - Crime Scene Investigation - you know, Marge Helenberger, Jorga Fox...

Oh okay, thanks for spelling it out! I haven't had a TV since 1995 (I don't mean for that to see like a "holier than thou" type of comment, just an honest explanation).

I've got some more thoughts I'll post later...

Fantastic, thanks! I look forward to that!

One quick question is it worth redoing the heads you have vs. getting another set from a yard and redoing them?

This is a great question! Since I have the camshaft and valve lifters already, the heads might be a good thing to hang on to (since they're some of the strongest evidence regarding the type of engine I originally received). I'll ask Tom about this.

It sounds like you have a good build coming along, 500ftlbs at 2k is going to move you well, it's almost naturally aspirated diesel territory. Probably a good 2.5" mandrel bent exhaust with a 2" H in the pipes and it should be over 500 at 2500rpm. The compression looks good, should be interesting to see how it runs when done.

Okay, great! So based on what you see so far, what you know about my truck (8,100lb GVW F250, 3.73 D60, T18), would you say this new build is much better suited to my situation?

Am I correct in thinking that this build should perform well across a wide range of RPMs? I remember hearing that the previous build would be "peaky," meaning that it would perform best within a narrow RPM range. And since my T18 is a rather wide ratio transmission, it wasn't well suited for that.

Funny, when I was looking for the bad from PU I saw where a guy on the vintage mustang forums was looking at them for a 302 based motor and was turned to Keith Craft instead and got a really nicew motor for around $6-7k.

This doesn't surprise me! One thing I've learned from this experience is that a top notch engine builder can really do a lot for $6-7k.

PS, when it's in are you going to run it up to Tom and let him tweak it a bit or at least check it out?

I will most certainly be driving it back to Tom's when it's installed! Not only for him to look over and do some tweaking, but for him to have a chance to test drive the truck! This would not only be fun for both of us, but would give him a chance to observe its behavior and recommend changes to the drivetrain to better suit the truck, if any come to mind. For instance, he might recommend going from 3.73 to 3.25 or 3.00, as you mentioned earlier in this thread. Nothing beats experience when it comes to evaluating a vehicle, I'm sure!

By the way, I mentioned that idea to him during my last visit (going from 3.73 to 3.25 or 3.00), and he recommended sticking with the 3.73. At least at first to see how I like it! He said that his 1970 F250 (428/C6) also had a 3.73 rear and he liked that ratio a lot.

IAmTheWreckingCrew, Robert, and Jamie, thanks for your excellent advice!
Robroy

[Ranchero50]

Robroy, the only real weak link I see is the tranny. I think you'll want an OD setup so it's not running too many revs on the interstate.

Jamie

[robroy]

Hey Jamie, thanks for replying!

You're probably right about the value of having OD! And I guess with all the low RPM torque that this thing will generate, it would handle a tall OD gear pretty well.

I know it would be easier to implement that now (with the engine and transmission removed), but I'm going to delay that until next time I have the truck apart. There are really many things that I haven't done on this truck, but I want to "draw the line" about as far as I've gone for now. I'm certain that I'll crack in to it again after a few years! In the meanwhile, I won't plan on doing a ton of freeway driving with it.

Thanks again Jamie!
Robroy

[70_F100]

Robroy, one point that maybe you haven't thought of, and it just entered my mind.

Tom seems to be a fine, upstanding businessman.

I don't know what kind of warranty you'll have on your new engine, but since Tom knows it's still going to be quite some time (I assume) before the truck is actually on the road, will he consider working with you on warranty time in the event that your build takes quite a bit longer?

This might be something you could discuss with him during your next conversation.

Just my

[robroy]

Good evening 70_F100 thanks for replying!

Robroy, one point that maybe you haven't thought of, and it just entered my mind.

Tom seems to be a fine, upstanding businessman.

I don't know what kind of warranty you'll have on your new engine, but since Tom knows it's still going to be quite some time (I assume) before the truck is actually on the road, will he consider working with you on warranty time in the event that your build takes quite a bit longer?

This is a good point! I'm sure this has to be a situation the runs in to often, since I'll bet the majority of the engines he makes are for project cars.

Yet you know, I'm actually planning on putting the truck back on the road very quickly. I'm not going to do much more work to it. In fact, before I discovered all the serious problems with the engine in early November, I'd planned on having the truck in driving condition by Thanksgiving! And I was on track with that plan (I think).

It's ironic for me to remember how this entire thing started out as an effort to simply get the truck back on the road (it wasn't running at all when I started out). Then I couldn't resist getting fancy with stuff as I ripped in to it!

But regardless of that, your idea's a smart one and I'd be curious to hear Tom's strategy for dealing with this type of situation!

This might be something you could discuss with him during your next conversation.

Indeed! I'll ask about this.

Thanks very much 70_F100!
Robroy

[fomocoguy]

Sooooo, when do you plan on calling PU? The suspense is already killing me...

[DuckRyder]

Tom is very good at explaining things, at least it appears so to me. He's very patient and you can see he cares about what he does. The enthusiasm shows through.

[*] Using the 428-sized pistons, the engine will have 406 CID.

A good number, no replacement for displacement and all of that...

[*] Tom would like to build the engine with 9.7:1 compression. He likes this ratio because there's a little room for carbon build up before the compression gets so high that detonation becomes a real problem (on high octane pump gas).

Should be good, depending on the cam and ICA (Intake Closing Angel) will probably take pump premium. I am sure Tom will tailor the static to the cam to get a street-able Dynamic Compression Ratio.

[*] I asked Tom about what main upgrade came to mind, if I were going to spend a little more cash than his initial build idea. Tom said the #1 upgrade would be a roller camshaft and lifters! That adds around $700 to the total price, but as I understand it, will prevent the same type of camshaft failure the engine already suffered. I also heard that the engine will produce more torque with this roller camshaft and lifter setup.

I agree whole heartedly, a roller cam can make a bigger cam "act" like a smaller cam. The roller lifters decrease friction and drag in the engine and live better with current off the shelf oil. You heard Tom reference the "additive situation" several times. Once the break in of a flat tappet cam is done its less prone to fail, but they can and do fail in use and the oil situation only makes it a greater possibility. The more radical the cam, the more risk.

[*] Based on Tom's advice, we agreed that I'd go with a Crower roller camshaft (I forget which brand he recommended for the lifters, but naturally they'd be selected to match the camshaft).

We have talked a bit via PM about this, Crower is a great cam, and I feel the roller is the way to go particularly with HIPPO (HIgh Pressure Pin Oiling). Let let Tom determine the grind based on your application.

[*] With low RPM torque in mind, Tom recommended selecting a Crower grind that will result in a mild "muscle car" type of idle at around 650 RPM. Note that the previous camshaft setup required a 900 RPM idle.

Sounds appropriate...

[*] I heard from Tom that unlike their flat tappet camshafts, the Comp Cams roller camshafts are OK. Despite this, since I'd heard good things specifically about the Crower parts Tom said he'd stick to those.

Can you expand at all on this, it sounds like Tom might not care for Comp flat tappet cams (Like me), did he have bad experiences? I really do like Crower, I believe they are still family owned and not part of one of the huge conglomerates, I like that!

[*] ARP head bolts will be used. The engine already had ARP connecting rod bolts, so those can probably be re-used.

Again, very good choice.

[*] With regard to accessory bolts, I declined Tom's offer to use ARP bolts for those too, since they're more of a cosmetic item there (I'm guessing). Do you think I made the right choice?

I have mixed feelings, they don't cost that much, the reduced heads can help access in places. It can probably be argued they provide more consistent torque. New bolts may be less apt to fail. I'd probably use them (what am I saying, I did use them).

[*] I asked Tom about stroker kits. He said that although it would increase the performance potential a lot, it would also add an extra $2,000 on to the price tag for the engine. And considering the type of performance he thinks he'll be able to build in to this engine with the standard 390 crankshaft, I heard that it probably wouldn't be worth it (in my case) for the cost involved. This said, I did hear that beyond the roller camshaft and lifters, the stroker kit would be his next suggested upgrade.

Since the rods appear good and it sounds as if the crankshaft will polish (polish and turn is a distinction) this becomes a matter of Cost/Benefit ratio, more CID is more displacement. If the 390 crank will simply polish up, then thats a minimal investment. If it requires turning to the next under-size, then a slightly larger investment. Some people feel that going .020 or .030 under on a crank weakens it, I think that is a non-issue here. I do wonder if Tom might have access to a 428 crank core to me a 300-400 additional investment to go to standard 428 would be worth it. (you'd have to change the flywheel too though).

[*] I asked Tom about the Edelbrock aluminum heads. Tom explained that he recommends those heads primarily for high horsepower applications (for light vehicles), because the increased flow through the ports can decrease exhaust temperatures and velocity, which can be torque-robbing. Tom went on to explain that he'll port my existing iron heads, and that removing material from the top side of the ports is more effective for building torque than removing from the bottom side.

I'd go with Tom's preferences here. I was glad to see the air cooled head being CC'ed in the video (what was that, Lycoming, Continental or perhaps Porsche?). He has the greatest experience with FE's and he knows what he can do. I don't know what I saw now, but I was thinking that PU had already put intake seats in and had machined them too deeply, which would get into welding to fix and so forth. I hear Tom talking about going with CJ sized valves, which should take care of the seat issues.

[*] Tom mentioned that the new engine should have a 160 degree thermostat, and will like to run between 165 and 170 degrees.

Again, follow his advice.

Tom entered some numbers in to his Dyno 2000 software and provided me with these printouts. Although the numbers aren't finalized yet, this shows the performance and temperament ballpark.

Before showing me these numbers, Tom explained that although software dyno numbers can be very misleading, these particular ones should be fairly close. To support this, he showed me the comparison between the Dyno 2000 output for his Mustang engine and the actual dyno output, and they matched within just a few horsepower all through the RPM range! It was really impressive.

Scans omitted for clarity

It looks to me as if Tom is using very conservative entries which in my experience is the way to go with DD2000 (and later versions, I actually think it got worse with newer versions)

I should see if Tom will scan a copy of the draft invoice he wrote for me, so I can post that here too. It's detailed and itemized.

That would be interesting.

For the moment, I asked Tom to pause activity on the engine until I'd discussed its parts and specs here for a short while. Maybe y'all (there it goes again) will have some advice for me on this!

Perhaps we might, I think we all have confidence in Tom and that he will lead you in the right direction, we might offer advice for you to discuss with him. I think he (with you of course) knows what he has planned globally.

I think it is important to remember that the F250 has a larger tire (what ~31 - ~32" diameter?) than what most of us are used to (~28") so the 3.73:1 gear won't have the same cruise characteristics as an F100 or Mustang/Torino/Fairlane/Comet/Galaxie etc, etc...

[robroy]

Good day FoMoCoGuy and Robert, thanks for your great replies!

Sooooo, when do you plan on calling PU? The suspense is already killing me...

Thanks for being interested! I have a head cold at the moment and need to compile my main points before contacting them, but it will be this week for sure. You guys will be the first to know what their response is!

Tom is very good at explaining things, at least it appears so to me. He's very patient and you can see he cares about what he does. The enthusiasm shows through.

Indeed! You should have seen the look in his eyes when he was reviewing all the camshaft options with me. He said, "I love doing this," and he looked like he was unwrapping a model train set on Christmas morning!

[*] Using the 428-sized pistons, the engine will have 406 CID.

A good number, no replacement for displacement and all of that...

Excellent! This reminds me that I heard from Tom that when an engine bore is increased, it can make the engine more difficult to cool. I also heard that in this situation it wouldn't matter very much (I'm guessing because the FE engine simply has a lot of "meat"). What are your thoughts?

[*] Tom would like to build the engine with 9.7:1 compression. He likes this ratio because there's a little room for carbon build up before the compression gets so high that detonation becomes a real problem (on high octane pump gas).

Should be good, depending on the cam and ICA (Intake Closing Angel) will probably take pump premium. I am sure Tom will tailor the static to the cam to get a street-able Dynamic Compression Ratio.

It looks like I have some reading to do before I'll understand these terms (other than "pump premium" ), but I'm also sure that he'll take tremendous care with the specifications!

[*] I asked Tom about what main upgrade came to mind, if I were going to spend a little more cash than his initial build idea. Tom said the #1 upgrade would be a roller camshaft and lifters!

I agree whole heartedly, a roller cam can make a bigger cam "act" like a smaller cam.

I heard this same thing from Tom! In fact, when he heard from me that I was ready for the roller camshaft setup, he increased the aggressiveness of the camshaft lobes in Dyno 2000 to suit.

The roller lifters decrease friction and drag in the engine and live better with current off the shelf oil.

This I like very much. When an upgrade can increase both performance and reliability, it's well worth an extra $700 to me!

You heard Tom reference the "additive situation" several times. Once the break in of a flat tappet cam is done its less prone to fail, but they can and do fail in use and the oil situation only makes it a greater possibility. The more radical the cam, the more risk.

Quite interesting! Yeah I've very glad Tom mentioned the roller camshaft configuration--it sounds like a big improvement for the engine.

[*] Based on Tom's advice, we agreed that I'd go with a Crower roller camshaft (I forget which brand he recommended for the lifters, but naturally they'd be selected to match the camshaft).

We have talked a bit via PM about this, Crower is a great cam, and I feel the roller is the way to go particularly with HIPPO (HIgh Pressure Pin Oiling). Let let Tom determine the grind based on your application.

Fantastic! I still need to read the article you sent me (thank you very much for that)!

[*] With low RPM torque in mind, Tom recommended selecting a Crower grind that will result in a mild "muscle car" type of idle at around 650 RPM.

Sounds appropriate...

Yes I think so. Of course as you know, my lack of experience with different types of engines influences my desires here a lot. The only vehicles I've ever driven that had fast idling engines also happened to have funky/broken engines. So I've never experienced the fast idle situation with a super healthy engine (an engine made that way on purpose).

[*] I heard from Tom that unlike their flat tappet camshafts, the Comp Cams roller camshafts are OK.

Can you expand at all on this, it sounds like Tom might not care for Comp flat tappet cams (Like me), did he have bad experiences?

If I remember correctly, I did hear Tom voice disapproval of the Comp Cams flat tappet camshafts, although I don't think I asked him for any anecdotes (or I've already forgotten--sorry)! This said, I will definitely be recording more video of Tom's wisdom before this adventure is complete, and I could ask him specifically about this.

I really do like Crower, I believe they are still family owned and not part of one of the huge conglomerates, I like that!

Excellent!

[*] ARP head bolts will be used. The engine already had ARP connecting rod bolts, so those can probably be re-used.

Again, very good choice.

Great!

[*] With regard to accessory bolts, I declined Tom's offer to use ARP bolts for those too, since they're more of a cosmetic item there (I'm guessing). Do you think I made the right choice?

I have mixed feelings, they don't cost that much, the reduced heads can help access in places. It can probably be argued they provide more consistent torque. New bolts may be less apt to fail. I'd probably use them (what am I saying, I did use them).

I see! Yeah I'm not trying to save cash on this specifically--I just didn't understand what meaningful benefits they could provide. The accessory bolts were supposedly brand new from Proformance Unlimited's build, yet you're right about the cost being pretty small. If there are indeed benefits (beyond cosmetics) to doing so, I'll go for this without hesitation!

[*] I asked Tom about stroker kits. He said that although it would increase the performance potential a lot, it would also add an extra $2,000 on to the price tag for the engine.

Since the rods appear good and it sounds as if the crankshaft will polish (polish and turn is a distinction) this becomes a matter of Cost/Benefit ratio, more CID is more displacement. If the 390 crank will simply polish up, then thats a minimal investment. If it requires turning to the next under-size, then a slightly larger investment. Some people feel that going .020 or .030 under on a crank weakens it, I think that is a non-issue here. I do wonder if Tom might have access to a 428 crank core to me a 300-400 additional investment to go to standard 428 would be worth it. (you'd have to change the flywheel too though).

Thanks for giving me your thoughts on this! I could ask Tom about whether or not he has a 428 crankshaft. I might hesitate to do this though, because if the 428 crankshaft did cost around $350, and the flywheel around $250, it could start to add up. After all, I already own a brand new Centerforce 390 flywheel. But I will ask Tom--thanks very much for this suggestion!!!

Also thanks for letting me know about the big distinction between simply polishing and turning a crankshaft. I wasn't fully aware of this! I'll re-watch the video of Tom discussing the crankshaft to get more clear on what he had in mind (one of the great benefits of those videos)!

[*] I asked Tom about the Edelbrock aluminum heads.

I'd go with Tom's preferences here. I was glad to see the air cooled head being CC'ed in the video (what was that, Lycoming, Continental or perhaps Porsche?).

That was a Porsche head (he discussed it with another customer who stopped by)!

He has the greatest experience with FE's and he knows what he can do. I don't know what I saw now, but I was thinking that PU had already put intake seats in and had machined them too deeply, which would get into welding to fix and so forth. I hear Tom talking about going with CJ sized valves, which should take care of the seat issues.

Indeed, he'll be using over-sized, stainless valves. Last I heard that would be part# 2090165 (are these CJ sized valves)? I also noticed that he used the CJ valve strategy on HOWDY69's 410 (416 actual CID) engine.

About what was done to the heads by Proformance Unlimited, I wasn't entirely clear if they'd machined the seats too deeply, or if the seats hadn't been freshly machined. Maybe I can understand more about this by re-watching the "Heads" video.

It looks to me as if Tom is using very conservative entries which in my experience is the way to go with DD2000 (and later versions, I actually think it got worse with newer versions)

I see! Excellent. From what I've heard from Tom, he does tend to make very conservative performance estimates. Even the amazing actual dyno printouts he has all over his wall were done with the engines tuned as they would be for actual driving--he didn't "doctor them up" to get those numbers.

I should see if Tom will scan a copy of the draft invoice he wrote for me, so I can post that here too. It's detailed and itemized.

That would be interesting.

Okay doke, I'll ask for it!

For the moment, I asked Tom to pause activity on the engine until I'd discussed its parts and specs here for a short while. Maybe y'all (there it goes again) will have some advice for me on this!

Perhaps we might, I think we all have confidence in Tom and that he will lead you in the right direction, we might offer advice for you to discuss with him. I think he (with you of course) knows what he has planned globally.

Indeed! I really appreciate the generous advice you guys have offered, and it does help me communicate more effectively with Tom--it helps to have heard about these options in advance!

I think it is important to remember that the F250 has a larger tire (what ~31 - ~32" diameter?) than what most of us are used to (~28") so the 3.73:1 gear won't have the same cruise characteristics as an F100 or Mustang/Torino/Fairlane/Comet/Galaxie etc, etc...

This is news to me! Thanks for pointing this out. From the small amount of experimentation I've done with RPM calculators, I have noticed what a big difference an inch or two of tire diameter can make.

I'll certainly try the truck out with its current setup for a while before making any changes. I'll probably be doing very little freeway driving for a few years anyhow, since I'll most likely be taking a route through town to work (instead of the freeway).

Last night I was reading, "How to Rebuild BIG-BLOCK FORD ENGINES," by Steve Christ, and came across this passage (page 32):

Some 361/391 FT blocks are cast with thicker main-bearing webs and additional ribs in between. This increases their weight about 20 pounds over the FE 390. Heavier 361/391 FT blocks do not have the 352 as cast on the left front of the standard FE block. Most heavy blocks have a mirror-image 105 on the left front, though this is missing on some blocks.

And in a caption under an image of the "105" on a block (on page 33), Steve Christ says:

In place of the 352 found on most FE blocks, many heavy-duty FT cylinder blocks have mirror image 105 on left front. In some cases, this area is left blank on heavy-duty blocks. HD blocks have additional main-bearing support and thicker main-bearing webs.

So! Does this mean I've scored with this 105 Mirror block even more significantly than I initially thought? And does this mean that I've actually got an FT block instead of an FE?

If so, would this be more accurately called an FT engine (instead of an FE)?

FoMoCoGuy and Robert, thank you both very much for your truly excellent replies!
Robroy

[ToughOldFord]

More than likely not. The FT usually isn't drilled for side mounts and to use a FE distributor you'd have to use an adapter as they have a larger hole in the block.

[ToughOldFord]

In fact, here's a good thread on FT differences.