I have a question for those more experienced that me regarding carburetors and intake manifold design. I currently have an internally stock '84 351W., but with a 2 barrel non-feedback carb. and Duraspark II ignition. The intake manifold is the stock Ford with the EGR port cast in but now blocked off. Future plans call for shorty headers with no cats.

I have an Edelbrock Performer manifold #3781, that I got cheap from Ebay. This manifold is for EGR engines and is basically a 2-piece manifold; a lower manifold and an adapter plate for 2 barrel carb with an EGR boss cast into the plate. They also make a #3783 manifold which is the same but uses a 4-barrel adapter plate. The adapter plates are available separately to convert one to the other.

Now my question!! How much will I gain, if anything, by switching from stock Ford manifold to the #3781 manifold with my stock carb. (1.21 venturi size, I think)? Also what could I expect by swapping adapter plates and running a 600 CFM Edelbrock carb.

I know that numbers are not possible here but would appreciate generalized estimates as to gains (none, slight, significant etc.) The truck's use is for general household hauling (firewood, mulch etc.), hunting, bad weather transportation and a little bit of off-road playing.

Any comments gratefully accepted!!!

 

For the cost of a set of gaskets, I say just put it on and see.

I need to replace my intake front and rear seals, and if I had another manifold I would go ahead and put it in.

Performancewise, I wouldn't expect much difference. If your stock manifold is iron, then you would save a few pounds....

 

Yea, I say go for it also. I replaced the stock iron manifold early last year with the non-egr version of the manifold you have there.

Woke it up a little bit, smooth power all the way through the rpm range. I'm happy with it, and as pointed out, a weight savings.

Looks cool too!!

Also, if you do any other power add-ons, the new manifold will compliment them. Good bolt on item. Do it.

 

Well I checked the stock manifold and it is aluminum, so no weight savings. Unless someone thinks there is a performance advantage with the Edelbrock, I'll just hold off on it until I decide to try a 4-barrel, then buy the other plate and see what happens.

Edelbrock does claim a torque increase with their manifold, but lots of people claim lots of things that "ain't necessarily so".

Anafiel: with yours, did you change carbs, or just change manifolds to the Edelbrock? When you say it "woke it up " a little was that from just the manifold change or what?

 

I doubt you will feel much difference with the original 2bbl and the aftermarket intake. But you will feel a difference if you swap in the 4bbl carb. They run so much better with a aftermarket 4bbl on them.

 

That's the truth!

 

When I first got the truck, there were issues stemming from the PO's haphazard removal of the emissions stuff. I had a lot of cleaning up to do. One of the issues was that the EGR system was removed, all but the EGR plate under the carb. So I decided the go ahead and swap out the manifold while I was cleaning up all the "hanging" issues.

I would like to say that it was just the manifold swap, but I can't. All I can say is that I now make good power through the RPM range, especially in the low end, and I'm extremely happy with it. Quick and easy starts, even when cold. Good power, and I'm not complaining about the gas mileage.

I'm sure I could do loads better with a little head work, and a nice set of headers.

Oh, and the truck was already 4bbl, or as my air cleaner points out, "351HO 4V"

 

Thanks for the replies, guys. I think I'll just leave the stock manifold on with the 2150 for now and go ahead and order the 4-bbl plate so i have it.

I have a few other things to clear up, such as whether this truck has too much rust to rework economically. If not i have another truck i can swap this engine into. I would really like to stay with the 80-86 years because I like the style better but the other truck is an '89 F250 4x4 with a tired 302 engine (plow truck).

The 351W has less than 20K on a professional rebuild so I am going to use it in some 4x4, one way or another. What ever I use it in will probably end up with shorty headers and a 4-bbl carb, so the manifold will eventually get used.