What Makes Ford Intakes Bad?

[colnago]

Yes, my "rolling classroom" is for me learning. Right now, I'm trying to learn how/why things are good/bad. I completely understand when/why people suggest that I have to look at the end goal. Unfortunately, I'm also finding that I can't ask questions about a single item.

This thread is a good example. All I really wanted to know is why Ford 4BBL iron intakes are bad ... or if they're bad, or when they're bad, or ... ? Are they fine on a low-RPM truck, but bad for a street racer? Are they bad because they're heavy? Are they bad because you are limited to what work you can do on them? Are they bad because a Performer RPM is cool?

Instead, the feedback I get is that the Edelbrock 1405 is crap. My camshaft question quickly went south, so I had the thread deleted and I sent apologies via PM to those at which I snapped.

But my highest priority is the learning. Again, the what/when/why of components. Anything is an option. Anything can be swapped. Even book recommendations would be appreciated; maybe that's where my learning needs to move for the time being.

Thanks for your recommendations, and for listening.

Joseph

[Ranchero50]

OK, 99% of the opinions you'll read about on the net relate to performance above and beyond what Ford intended the vehicle to perform. These trucks were built to tool around between 45 and 55 mph in winter cold and desert heat. Since you are intending to keep it within the stock performance limits there's no real need to add a cam or 4 bbl intake. At 3k you're making almost cubic inches in torque with the stock setup. The stock cam tops out around 4k, 4500 with a worn chain. Look at the bottom of the RPM chain cams and compare them to the factory parts. You're going to have a hard time finding something that works as well as stock at what you are asking. The return just isn't worth the investment.

Where you can gain is efficiency. If something doesn't make the engine more efficient, skip it. Cams, headers, port work, 4 bbl and carb. Skip them all. Especially the 4 barrel as you'll not push it hard enough to open the secondaries and it's a tuning PITA.

Find a 1.33 venturi 2100 and go with it. Google some of the CFM / HP calculators. 352 x 3000 / 3456 gives 305.55 cfm. A 1.33 at 1.5" of HG is 305 cfm. Boom, done and much easier to tune and keep tuned.

[colnago]

Ranchero,

Thanks! That's exactly the info that I was looking for.

Joseph

[colnago]

... some nice rockers (getting harder to find) and put some headers, 2.5 inch duals and Holley Sniper on top of an open spacer ...

Not exactly things I had considered, but what rockers would you recommend (just some nice stock rockers, or aftermarket), and why the open spacer? I currently have a 1" four-hole spacer; I thought the general rule was to use open spacers for higher RPMs, but I don't have any experience with trying different types. I don't know anything about the Holley Sniper, but I'll look into it.

Thanks,

Joseph

[DuckRyder]

[

...
This thread is a good example. All I really wanted to know is why Ford 4BBL iron intakes are bad ... or if they're bad, or when they're bad, or ... ? Are they fine on a low-RPM truck, but bad for a street racer? Are they bad because they're heavy? Are they bad because you are limited to what work you can do on them? Are they bad because a Performer RPM is cool? ...

Pretty much all of that is why they are considered bad. I think to really determine if they are in fact bad you would have do some testing (Jay Brown wrote an entire book about this, though I’m not sure how much he went into the why, I need to pick it up) you could flow it on a flow bench, you could run it on a dyno, you could cut it open and look at the ports.

You can get a general idea though by looking at a standard intake in comparison to factory performance intakes like the Cobra Jet and Police as well as aftermarket, I think you will find that rise is higher and the runners are larger in the plenum area in particular.

Still for a stockish motor IMO it’ll work fine.

... some nice rockers (getting harder to find) and put some headers, 2.5 inch duals and Holley Sniper on top of an open spacer ...

Not exactly things I had considered, but what rockers would you recommend (just some nice stock rockers, or aftermarket), and why the open spacer? I currently have a 1" four-hole spacer; I thought the general rule was to use open spacers for higher RPMs, but I don't have any experience with trying different types. I don’t know anything about the Holley Sniper, but I’ll look into it. ...

On the rockers, for a mild engine like we are talking about probably rebuild the factory ones. Erson is out of production AFAIK, Harland Sharp and Comp make roller rockers and I believe Crane and Sealed power still make cast ones.

The open spacer is because the Sniper has demonstrated that it likes an open plenum...

I don’t entirely agree with Jamie here but I also don’t entirely disagree either. In particular I think you can gain some efficiency in a more modern camshaft design.

Still I almost said last night that a stock rebuild would do what you are asking it to do. My suggestion more succinctly is to build a slightly modernized “car” motor.

Might have a look here too:

https://www.428cobrajet.org/id-cam

https://www.428cobrajet.org/id-intake

[colnago]

Robert,

Thanks for your detailed reply.

The main reason that I keep asking these component-type questions is because of the engineer in me. I'm looking for cause and effect. For example, if I change cam profiles, and the performance increases, I can credit it to the change in cam profile. But if I change cam profile, AND put headers on, is the improvement from the cam, or the headers, or both? I just lost my cause and effect.

With the intake manifold, it's the same thing. The only difference is that I have a 2BBL manifold and 4BBL manifold already leaning against the garage. If I modify the runners, ports, and/or plenum, what would I see, for better or worse? Since I already own the manifolds, I'm only out the time, and a set of gaskets. I can't ruin anything, and maybe I'll learn something on the way.

Keep on learning, and keep the old girl on the road. That's all I'm after.

Joseph

[colnago]

... and Holley Sniper on top of an open spacer ...

A Holley EFI system? That's an interesting suggestion. Not a direction that I'm too interested in, at this time (I'm having too much fun with my crap Edelbrock 1405), but an interesting idea for down the line.

Joseph

[colnago]

Ranchero50,

I would like to ask your opinion on a possible engine mod for me. Honestly, I can't see the truck ever going higher than 3500RPM, and that's only when cruising on the freeway. But, for the sake of discussion, let's say that I made the following upgrades:

- Sanderson Shorty headers (shorties for clearance issues), with 2-1/2" dual exhausts
- Edelbrock Performer RPM intake manifold
- Edelbrock Performer (non-RPM) camshaft (I think the 7106 camshaft is for higher RPMs)
- Either 352 block, crank, rods; or 390 (either one 0.030" overbore)

In your opinion (or anyone else; I won't hold anyone to anything), would I notice any difference, and where? If I had to do this in stages, what order would you suggest?

Thanks,

Joseph

[Jacksdad]

The Performer RPM intake seems like overkill for your application, Joseph. It's power band is 1500 to 6500 rpm - most of it is well above what you plan on revving it to. The Performer makes power from idle to 5500 rpm and would probably be a better fit for your application.

[1972hiboy]

What about the edelbrock SP2P? kinda hate to stir the pot at this point. but if fuel economy and low rpms are involved then it should at least be thrown out there. Small intake runners. so low rpm, elevated intake manifold velocity vs stock intake. granted the trade off is this manifold wont support race car rpms. But for a truck that lives in the sub 3500 range? could be beneficial. I have one around somewhere I have always been meaning to try it out for my own so sorry I don't have any real first hand experience with it.

[Jacksdad]

An SP2P could work because it's RPM range is certainly compatible with your intended use. They were Edelbrock's attempt to improve gas mileage and low end torque for truck applications, and they predate the Performer. They had long, skinny runners that sacrificed top end power for low end torque. Not well liked, but that was probably because everyone expects an aftermarket aluminum intake to do the opposite of what these things are designed to do. The SP2P is pretty much done by 4500 rpm at best.

[colnago]

Hmmm, I don't know a thing about the SP2P. I've always heard that the 2105 is not much better than stock, but I think I'll reconsider and do more research.

From the feedback I received here, plus reading elsewhere, I think I need to rename this thread. My new understanding (please correct me if I'm wrong) is that the stock manifold isn't "bad," it was just designed for a particular use, and 50 years later, our needs are different. So, if I want stock performance, then stock parts are fine.

Thanks, everyone, for your feedback and your patience. It is not falling on deaf ears.

Joseph

[Jacksdad]

The Performer is widely viewed as a copy of the factory intakes, but 1250 lbs lighter. Give or take.

It just feels like the Edelbrock RPM (7105) intake would be going in the wrong direction for your build because of the way it hikes the power band higher up the rpm range. If you're serious about not spinning this motor fast (I couldn't make that promise with a clear conscience... ), then a stock, Performer (2105) or SP2P intake would give you power from idle to your upper limit of 3000 rpm, resulting in a useful spread of almost 2500 rpm. Keeping the same "red line" while moving the power band up with a 7105 intake would now mean it doesn't start making decent power until 1500 rpm - now you only have 1500 rpm when the bulk of the work is being done. A smaller (or stock) intake would be the one I'd go for on a build like that. I know you're going small on the carb, but putting it on a high flowing performance intake like the RPM would be a horrible combination. You might run into problems with your stock converter too, as I believe a C6 stalls at 1500-1800 rpm.

My 351W is being built with parts that will hopefully work best together from idle to 1500 rpm - Performer intake, fairly mild performance cam, iron heads (albeit GT40Ps), stock converter, and 650cfm vacuum secondary Holley. Even though I'm setting myself an upper RPM limit of about 5500 RPM, I still wouldn't consider the 7105 because it would take away from the bottom end, and I'm primarily building a truck engine...with a slightly nasty side.

[DuckRyder]

I think the proposed engine would feel stronger than a stock engine across the usable range, however I agree the RPM is a mismatch. I doubt it would make any more power than a stock or Performer intake and it might feel softer on the low end if you could drive it back to back.

By choosing the RPM to go with a performer cam, you’re creating the sort of mismatch that Edelbrock power package seeks to avoid,

I do think the Performer cam is not a bad pick for the intended use.

[Jacksdad]

By choosing the RPM to go with a performer cam, you’re creating the sort of mismatch that Edelbrock power package seeks to avoid...

Totally agree.