Posted By: 340clone
Four barrel carb for 318 - 02/14/14 01:58 AM
My Challenger has a small block 318 and I am running a '70 340 intake with a '70 AVS Carb. I think it's too much carb for this motor.
Any recommendations on a lesser CFM, AVS style 4bbl carb (Edelbrock) that I could use to tone it down and keep the same look?
Thanks!
Posted By: RapidRobert
Re: Four barrel carb for 318 - 02/14/14 03:33 AM
That ain't too much carb for it. I'm sure it is significantly less than 600 cfm (measure its' bores). What symptoms are you having? I have an Eddy 1406 600 cfm on a DD 318 & it runs flawless. All OE AVS's are emission carbs and are lean plus the air door adjustment. I'd suggest converting to Eddy performer 2 step rods/primary jets from a strip kit with sizes close to whatever is in the AVS right now maybe going several thou smaller on the "cruise" step for a start. You WILL notice the difference but holler back with what's going on
Posted By: dogdays
Re: Four barrel carb for 318 - 02/14/14 05:53 AM
When properly adjusted, the air door will make the carburetor only as big as the engine needs.
I am using a Holley Street Avenger 570 on my 318 and it isn't too big. The AVS is most likely smaller, Chrysler didn't put a lot of carb on their regular engines.
R.
Posted By: 340clone
Re: Four barrel carb for 318 - 02/14/14 07:01 AM
The issue I'm having is that it seems to be running too rich. Even when I think it's properly tuned, It's still has a bit of a gassy smell to the exhaust, enough to make your clothes reek! LOL. Engine only has about 500 miles on it. A friend of mine said it was that the carb was too much for the engine. I didn't see how either, but I've adjusted the heck out of it with no real luck...
Posted By: roe
Re: Four barrel carb for 318 - 02/14/14 07:09 AM
Be careful, running excessively lean will give you the same smell of fumes. That's what happened to me, and leaning it out to fix th "Rich" running, fume smelling condition only made it worst.
Posted By: Baxter61
Re: Four barrel carb for 318 - 02/14/14 07:10 AM
I ran a holley 3310 with a pro form main body on a 7.5:1 318 with 360 heads and an air gap intake. It would roast the tires from a slow roll, ran good when rpm'ing, and got 20+ mpg. The carb aint too big, to reiterate from whats been said it just needs to be tuned, those carbs dont flow what thartre "rated" at
Posted By: slantzilla
Re: Four barrel carb for 318 - 02/14/14 12:57 PM
I would be more concerned about the port mismatch/vacuum leaks.
Posted By: Supercuda
Re: Four barrel carb for 318 *DELETED* - 02/14/14 01:44 PM
Port mismatch?
Right, keep believing that one
Posted By: RapidRobert
Re: Four barrel carb for 318 - 02/14/14 04:55 PM
I would check the float levels/float saturation/float linkage/needle condition as it might be a carb rich issue. What adjustments have you done? do the boosters drip at idle? As said a lean misfire can kick up the same symptoms as the unburned mixture just goes out the tailpipe where you smell it just like you would smell it if it was excessively rich from a carb issue. regarding a vac leak, how does it run/is there any hesitation anywhere?
Posted By: pinkduster
Re: Four barrel carb for 318 - 02/15/14 03:51 PM
Back in the late 80s and 90s when we were all driving 318s (old style too) we used to just use the Holley 600 with vacuum secondaries. No problems. Great carbs right out of the box. I've been wanting to put one on my 69 Charger, just hasn't happened yet.