390 longevity without leaks

[Happy_Camper]

Hey guys,

What kind of miles are you putting on your 390s without having to deal with oil leaks?
How does longevity of the 390 compare with the 460 as far as external oil leaks go?
For that matter how does the mechanical longevity compare between the two?

Both engines will be modified to get into the area of 450+lbs-ft of towing torque. And that will be about 60% of it's use. I'm hopeful (from what I've read), that neither engine will need to run a CR higher than 9.5. And I've dropped the idea of turbo on the 390.

Other than what I've been reading on here, the FE forum, and a few other places, I don't really know squat about either engine. I've always been a small block guy. The 460 has an advantage of EFI and more displacement, as well as a better (from my limited view) intake manifold setup.
Either way, 390 or 460, it seems pretty even money (about $6K complete) for what I want.
There have been some pretty good deals lately on 460s with C6 transmissions, and before I start spending money in either direction, I'd appreciate your experienced thoughts on this.
Thanks!

[Happy_Camper]

Anybody have any thoughts, or personal experience, with both engines?

Thanks,

[fordman]

without leaks depends on how you put your gaskets on the outside of the engine. how long? i don't know. i like the fe. i dont care for the 460.

[averagef250]

I have never seen a carb 460 make 150K and only seen a couple EFI ones make 200K. I've seen dozens of 360's, 390's and one Merc 410 make it well past 250K miles untouched.

I put 140K daily driver and very heavy tow miles on a 390 built for me by Mick Gray. I have absolutely no clue how anyone could spend $6K on a truck 390 though. I did everything you can do to one short of aluminum heads and had under $4K into it parts and machine work. It was a .060" over torque plate honed D4TE block, early crank and rods, hyper 9:1 pistons with bowl hogged D2 heads sporting stainless valves/hard seats, erson full roller valvetrain and a Crane 901 cam, hedman headers, dual 2.5's with a crossover, Cast iron 67 car 4V intake, 600 Holley, DUI HEI distributor. Stock volume oil pump, .020" oil restrictors in the heads,SVO windage tray. 10w30 castrol GTX

The only issues I had with that engine were valvetrain related. I bought pushrods from DSC that came apart in the engine. Do not under any circumstances give you money to that slimy piece of trash selling chinese crap as high end stuff. Comp pushrods are excellent BTW.

The engine ran excellent, I have no doubt it would out pull any truck 460 I've ever driven lb for lb. If I was conservative I'd say 375HP and 450 TQ with an unbelievable amount of power from 1600-2500 for a gas engine. For the weight and grades that engine pulled I can't see how it was possible unless it was making over 500 lb/ft at 2500. It hit a brick wall at 4500, but you'd better have some nuts to take it there. 4500 literally seamed like 6500 the way it pulled. I very rarely took that engine over 3500, never ever needed to. The engine got it's best mileage right around 2300-2600 RPM.

I pulled and sold the engine when I tore the truck down and new I was installing a diesel when it went back together. The buyer wanted to see inside so I pulled the heads and a few bearing caps. The engine looked exactly the same inside as it did when I put it together. The only leaking was from the front crank seal, maybe a bit of wetness from the rear seal, but pretty dry for an old 2 piece seal motor.

[Happy_Camper]

Thanks for the input Dustin!

$6k is easy to spend on an FE when starting off with a block, timing cover, and oil pan. Add a lot of machine work, American made parts, and I would say $6K is low.

So I will continue to research this, while I track down all the leaks on the 390 and see what *has* to be done to fix them.

[averagef250]

Where are you at? I know there are many FE builders out there, but if you're around the NW Mick Gray's in Tigard Oregon and does outstanding work and has for the last 40+ years. He does dirt, drag and marine endurance motors for the most part, but happily does anything else you need except diesel and import stuff.

Also, I ran a couple different intakes on that 390. A performer that I liked a lot for low end. It had the best off idle torque, but liked to cruise around 2000 RPM, it really ran out of steam past 3000. The car 4V intake worked very well with only a slight off idle loss, but really shined in acceleration from 2500-4500. I tried a performer RPM with port fuel injection and a megasquirt controller for the last few thousand miles and didn't like it. The EFI was nice, but the RPM lost all bottom end power. It made power from 2500 on up and actually felt very nice all the way to 5500, I was very surprised how much that intake changed the feel of the engine. I didn't like it for a truck, and hated the fact it didn't have an exhaust crossover. It was a cold blooded SOB with the RPM, even with port injection. The car intake was my favorite, worked well and gave the engine a 100% stock appearance from the looks of it. Boy were riders surprised at how it ran.

[Happy_Camper]

Sounds good. I'm a couple of hours south of Sacramento. Got a *somewhat* local guy I use for machining on SBF stuff, but have never talked big blocks with him...

I'd really like to pump up the cubic inches via a longer stroke. With the right combination of parts it *should* make a torque curve that looks like the "Cliffs of Dover", While still being efficient.

Yeah, EFI needs long runners with high velocities, and good turbulence in the valve pockets to get good atomization on the bottom end. I've run up to 22" runners on a few small block EFI projects. They worked great... for a small block. But I wouldn't want to pull more than the average ski boat with one.

[OldRedFord]

Sounds good. I'm a couple of hours south of Sacramento. Got a *somewhat* local guy I use for machining on SBF stuff, but have never talked big blocks with him...

I'd really like to pump up the cubic inches via a longer stroke. With the right combination of parts it *should* make a torque curve that looks like the "Cliffs of Dover", While still being efficient.

Yeah, EFI needs long runners with high velocities, and good turbulence in the valve pockets to get good atomization on the bottom end. I've run up to 22" runners on a few small block EFI projects. They worked great... for a small block. But I wouldn't want to pull more than the average ski boat with one.

Have your heart set on EFI?

Im not sure on a 390, but Im building a 460. Bought a complete engine and tore it down to the block, only factory parts that i have kept are

crank
rods
heads
block
timing cover
oil pan
push rods
rocker arms

Ill be under $3000 by the time the engine is in the truck, and it should have no problem pulling 475 hp and at least 400 ft lbs of torque.

*edit* I will openly admit knowing I am leaving power on the table by not working the heads.

[sideoilerfe]

Mick Gray's in Tigard Oregon and does outstanding work and has for the last 40+ years. He does dirt, drag and marine endurance motors for the most part, but happily does anything else you need except diesel and import stuff.
.

Mick does the best work for the money in my opinion. He's the only guy I'll go to.

[Happy_Camper]

If he builds a good marine endurance engine, then he must know what he's doing. Man, that can be a very stressful application. Thanks for the recommendations!

Hey Tim,
At this point, I don't have my heart set either way. Although a trip to the camp grounds starts just about sea level, and can go over 8,000' with camping at 6k' or higher, so EFI does have some plusses.
On the other side, I installed and tuned a Quick Fuel Street carb with annular nozzles last year for a guy, and he swears it has amazing driveability, no matter the temps, or altitudes. I was pretty impressed with the quality, and tune-ability. Much better than any Holley I've ever done before. More on line with a Quadrajet (as far as ability to tweak everything goes). So I'd definitely step up to the plate for one of these.

I'll look forward to your progress on the 460 build. Will you have a chance to post a thread on your build? Or is it all ready there and I just missed it?

[averagef250]

[/quote]Mick does the best work for the money in my opinion. He's the only guy I'll go to.[/quote]

Mick and Paul are the best kind of people and do outstanding work. They do what they love doing and they're great at it. No BS and you always get more than you pay for. Mick can usually be found watching his engines go in circles at the Lebanon dirt track on friday nights and it's not uncommon at all to see a 1-2-3 finish of his motors.

[hotrodfeguy]

I think one advantage a 460 has over my beloved FE is the fact a stock 460 block can swollow a 4.5" stroker crank for 545 CI.

[averagef250]

One advantage the FE has over a 460 is it fits in our trucks. I know, lots of 460's are dropped in these things and they came in dentsides, but the fit is on the poor side and they are a handful to work on in there.

A huge stroker big block would be fun, but they aren't as practical as an off the shelf 390 or 460. From my perspective a well built 390 did anything I ever needed it to gracefully. If I did it again I might try a 410, just for kicks, but wouldn't at all be settling if I just went 390.

[Happy_Camper]

If the aftermarket 390 pieces weren't so dog gone expensive, the decision would be much easier.
440+ c.i. is plenty big enough for me.
More people need to start really building up their 390s so we can get "mass buying" discounts