i'm building a 318 poly to put in my 78 dodge truck, and i would like to know if anybody knows which intake makes the most power, the factory dual quad intake or the weiand 7503 single 4 ?

depends on the rest of your combo i suppose..?

dual quad will make pretty decent power, although it might be a little overkill for that few cubes (even though it was factory)...

weiand is supposedly a good intake, especially in the upper RPM's..

However, a lot of polyhead fanatics seem to prefer the factory 4 bbl unit...seems to give the best of both worlds for low end grunt, and mid range power..

But don't take anything I have to say as gospel, I haven't run any of them yet...i'll know come spring though...

check out the poly group on yahoo, they'll give you all the answers you need!

I had a six pack set up and the Weiand 4V for my 64 poly. I went with the Weiand for obvious reasons. It made decent power with Pertronix ignition and Spitfire headers.

For cool factor, go 2x4!

There are more ploy guys here than you think, and they tend to be quiet about what they are doing, but I personally know of one that is being supercharged, one that is being 2x4, and one that is MPEFI!

cool how was the spitfire headers? i've heard mixed about them. i would like to find a set of shorty or block huggers for my poly so i could run headers in my truck. i've heard that a place called stan's headers makes engine swap headers that supposed to poly powered trucks from 61-71 if that's the case i wonder if they would work on my 78? if you have any info about any of theses headers i'm dreaming about let me know it was hard enough finding my aluminum intake now the search starts all over again for headers,,

Next time you are at a store, look in Street Rodder magazine (or something similar). There is a company that makes hot rod headers for just about everything, and they are reasonable on pricing. I just can't think of their name right now...

I loved my Spitfires!

One note about the Weiand intake, it took me about 5 tries to get it to seal properly, and the casting was way wrong, needed much machining to get it to work. The QC ain't that great on them...

Here's what I found with my Weiand intake, many times

And the Spitfires

I am VERY HAPPY with my 7503 running the Holley 600 vac secondary carb. Stock cam, stock exhaust manifolds with 2.5" pipes. It completely changed the way the truck drives and feels. Mileage is up from 10 to 15 on the highway because the Holley is tunable.
There is no cheap way to do this, the 2-4s intakes are less expensive but require two carbs, the factory 4-barrel is rare and expensive, the 7503 is out of production and selling way over its old retail price.
I think there must be a better way, but don't know what! Fords used the evenly spaced intake ports, possibly something rom a 351 could be modified? I have also read about people trying to modify Firepower intakes to fit.

I think there would be a market for either an adapter to use another intake or a piece-built intake. Stick a valley cover on the block and bring the runners out from the flanges into a common plenum.

R.