RockStar1776

Howdy!

I need help building an understanding of the proper CFM rating I should look for when swapping the carb on my engine. My engine is a LA V8 318 with a carter 2BBl (no idea what the CFM is, maybe 300?). I'm thinking about putting on a 600 CFM Edelbrock 4BBl carb. Would this be too big?

Specifically, I'm looking at Edelbrock Performer series products. Links to the products I'm looking at below:

Carb: https://www.edelbrock.com/reman-perf...-egr-9900.html
Intake Manifold: https://www.edelbrock.com/performer-...ines-2176.html

Iowan

Not a fan of the Edelbrock carbs but it should work.
Heat soke and boiling the fuel from the bowl are a problem for that carb.

Archer

RS -

Is the 318 bone stock, or what has been done to it?
600 cfm is good with a mild cam, but might be a little too big for a stock cam/drive train.

IF you plan on doing the cam in the near future, then dealing with an over-sized cam temporarily might not be a bad thing.

BTW - what car, transmission, rear gears, etc???

Archer

Iowan

Carb size will not be a problem, any carb with vacuum controlled secondarys are very forgiving on size requirements. I would not hesitate to use a 600 Holley on a stock 318 and the Edelbrock carbs flow less cfm.

Coronet 500

That's a good package and a good place to start. The OEM cast iron manifold is a great piece and can be found cheap.

Skwerly

i used a 600 cfm holley on my plymouth and never had troubles. ran like a dream.

RockStar1776

Thanks for the reply!

The 318 is mostly stock, with the two small exceptions:
1. The original Lean Burn system was removed from the Air intake housing
2. The original Electronic ignition was replaced with a mechanical ignition system

I am thinking about pulling the engine soon and changing the cam, getting it re-bored with new pistons, maybe some other changes. It's currently burning A LOT of oil (2 quarts in ~500 miles), so I think these changes (especially redoing the cylinder walls and pistons) will help a lot.

The car is a 78 Aspen R/T with a 4-speed manual. IDK the exact specs, but I know that the diffy is high-geared.

Your thoughts?

RockStar1776

Dan-

Only issue is I'd like to go from the OEM 2 barrel to a 4 barrel carb. Is it possible to get an OEM 4 barrel intake manifold for a 318?

Archer

RS -

Now your options are wide open, based on how much oomph you want.
You'll just have to play off the gear ratio, unless you're planning on changing that too.
I'm pretty sure 4V manifolds are still around, but why not go aluminum (Edelbrock, Holley, etc)?
If you're going for a stock look, you can just paint or powder coat it.

Archer

Lostviking

Get it rebuilt before you spend any money elsewhere. A motor in that shape needs to be rebuilt. A 4 barrel isn't going to change that.

Yes, you can find a 340 or 360 intake for a four barrel. 360 will most likely be a thermoquad. Look for a used aluminum one instead. You see them fairly cheap all the time. BUT, get the motor running properly first.

Having said that, how about just swapping in a good running 360? You can find them for sale at pretty good prices on the Mopar groups on Fakebook. That's probably your best bang for your buck.

Scott93307

would you use it on a stock 340 manifold with an adapter plate? This is what I am leaning towards

RockStar1776

Scott,

I've bounced around a lot and my plans have changed since this thread started a couple of months ago. Right now I'm keeping the stock Carter 2 BBD setup and focusing on things like replacing the valve seals, etc that will help my 318 run better. Once my current motor is reliable, I am going to start looking for a 360 to rebuild bottom up over a couple of months while driving with the 318. I hope to have my new motor ready to swap in by Spring Break or so. On the new motor, I'm probably going to run an Edelbrock performer intake with a Holley 4160 that my buddy was able to get for free from work (needs rebuilt and is off of a GM, so needs mopar linkages).

Thanks for your interest, and lemme know if you have any suggestions pertaining to my current plans!