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Carb for a poly

Fury Guy

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Could anyone tell me what 4 barrel carb I should use on a stock 318 poly motor? I recently acquired a Weiand dual plane manifold and should I consider putting a mild cam in as well?
 
What Weiand manifold do you have ?
I did not know they made an aftermarket 4bbl manifold for the 318 poly.
 
I am not sure which one it is there are no numbers on it. I have seen pictures of a Weiand 4 barrel carb with the number 7503 on it.
 
The intake and a carb no bigger than a 600. I ran a Edelbrock 600 on mine with the same intake.Headers or a good dual exhaust,3.23 or 3.55 gears and you got a runner.Even with a stock cam. I installed 340 valve springs with the heads still on the car. Man did it wake that Poly up.
IMG_0819.jpg
 
I have a 600 Edelbrock on mine and it has headers, bigger cam and some port work.
 
Does the manifold look like this?
20180223_174431.jpg


This is a Weiand 7503. It has great top end power but sucks a ton of torque below 3000 rpm. For a mild engine or a daily driver it's not ideal. I swapped mine for a factory 4 barrel intake which is much better low down. Depending on your combo and if you haven't installed it yet, you might be better selling it and getting a factory 4 barrel intake instead if you can find one. I run a 600 Holley vac sec.
 
Yeah the down side is the Weiand is a single plane design and does give up some of the bottom end as 66Sat stated above.
Still it's better than the tiny stock 2 bbl.
 
Actually the manifold I have is a dual plane, it doesn't have 7503 on it. It just has the Weiand name 2 places. The manifold I have looks a little different from the picture above. And thanks Darter for the info, I will look for a 6oo Edelbrock. My intent was to use the stock exhaust manifolds and install stainless dual exhaust. And where would I get the 340 valve springs?
 
Would a Quadrajet work for me? I intend to drive the car on some long drives and would like some fuel economy.
 
I'm pretty sure that the only 4 barrel intake made for the poly was the 7503. I think it is a dual plane manifold. You would be better off contacting Gary Pavlovich - he will give you all the advice you need on your engine so you don't waste any money, and he supplies parts such as cams etc too. I'll pm you his email address - he's a great guy and will no doubt help.
 
The 340 valve springs were a single with a damper. I bought mine from Mopar when they were still available.
You can check with Mancini or Hughes Engines for equivalent specs.
Or if you are planning to change the cam get the springs matched to the cam you choose.
You can check with POLYSUPERPAC.COM for all kinds of Poly stuff.
 
Years ago, a friend had a Dodge Coronet 500 with a 318 poly engine, TF trans, 3.55 rear. We installed a Mopar cast iron 4 bbl manifold from, I believe a '62 or '63 318 poly engine (or maybe a 301 poly). We used a Carter AFB # 3854S, with velocity operated secondary throttle valves, in addition to the mechanical secondary throttle plate operation and re-curved the distributor. Car ran very well, crisp throttle response due to smaller primary throttle bores and venturii, decent MPG. NO experience with the Weiand manifold, but don't overcarb the engine, use 600 CFM max. The Qjet mentioned would be ideal.....but....an adapter is needed plus throttle linkage end trans kickdown linkage could be difficult to adapt.... just my opinion of course.
BOB RENTON
 
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Thanks to all for your advice. I am not good at speed tuning, I can tear an engine down and rebuild it but am ignorant when it comes to knowing what works well together to get the most bang for the buck
 
As several others have mentioned - you can't go wrong with a Holley 600 VS (4160) series carburetor.

Now, should you install a 'mild camshaft' - of course. .440 - .450-ish lift, 220-230* duration @ .050, 110 - 112 LSA. That will definitely provide a boost in both low-end torque and horsepower.

Now if you haven't done so yet, longtube headers will provide some of the greatest gains in average TQ/HP production across the board.

If you're not great at tuning, you need to purchase a wideband 02 gauge setup. It makes tuning very simple, no more guesswork and reading scolding hot plugs on the side of the highway.
 
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