Too much Carb??

Posted By: Erik

Too much Carb?? - 11/25/14 02:25 AM

I have an 800 cfm AVS that I picked up for my Barracuda. I built a 416 stroker for it and here are some of the specs:

416 cid
Edelbrock Performer RPM intake
Comp Cam 292H series .501 lift (I&E) 244 duration (I&E) at .050 106 centerline 110 separation
Dougs Headers w/ 2" primaries and 3" collectors
3" exhaust
4 spd
3.55 gears in rear

Do you think 800 cfm is too much for this setup?

Posted By: forphorty

Re: Too much Carb?? - 11/25/14 02:38 AM

Nope, but the headers are too big if they are really 2 inch primaries. The cam may be a bit big. Just depends on your personal preference. I'm guessing it may feel a little soft under 3500.

Posted By: RapidRobert

Re: Too much Carb?? - 11/25/14 02:47 AM

You're fine on the carb. If you are up & running I would tune it. If those parts are a wish list as said I would get 1&3/4 pri tubes (maybe 1&7/8-depends). What heads? ported? what is the SCR? Is that measured?

Posted By: Dan Halen

Re: Too much Carb?? - 11/25/14 02:47 AM

Carb is ok, header primaries should be more like 1-3/4 and not enough gear for that cam.

Posted By: Erik

Re: Too much Carb?? - 11/25/14 02:49 AM

I was wrong on the headers - primaries are 1 5/8.

Heads are ported J heads.

SCR?? I don't understand that one.

Posted By: Cudajon

Re: Too much Carb?? - 11/25/14 02:53 AM

Tighten up the secondary air door so there's more resistance to its opening. Most of these I've worked on that door has been set loose so it flops open when the secondary's are opened. That's not the way it works. As the engine needs more air and fuel that secondary air door opens against the air passing over it. Also a good wide AF meter can tell you the AF Ratio to adjust the jets, metering rods, springs, etc. Thats a great carb set up correctly. There's a couple of good books out there on setting it up. Always go for the low hanging fruit before you think about changing things up. You can chase your tail forever doing that.

Posted By: fourgearsavoy

Re: Too much Carb?? - 11/25/14 02:55 AM

I think you will be fine with that carburetor and with a 4 speed I think the cam will be just right for a street car.
You didn't mention what you have for cylinder heads

BTW I think you could get more out of that combo with a 557 solid cam if you have the flow for it

Gus

Attached picture 8341038-moriaburnout.JPG

Posted By: Erik

Re: Too much Carb?? - 11/25/14 02:56 AM

Quote:

I think you will be fine with that carburetor and with a 4 speed I think the cam will be just right for a street car.
You didn't mention what you have for cylinder heads
BTW I think you could get more out of that combo with a 557 solid cam if you have the flow for it
Gus

Ported j heads

Posted By: 383man

Re: Too much Carb?? - 11/25/14 03:32 AM

I agree that carb is fine for your combo. I also agree with "Cudajon" as the secondary air door adjustment is very important on the AVS. If it opens to soon it may stumble and hesitate. Its important to have the air valve spring tension right so it opens at the right time. Many carbs also use the choke pull-off to slow down the air valve opening so its not to fast and dont bog down. But I dont think the AVS uses the choke pull-off to work with its air valve. Ron

Posted By: RapidRobert

Re: Too much Carb?? - 11/25/14 06:58 AM

Clarified combo list sounds good ex for guys said the cam is too much (I ain't a cam guy). Dial in the carb/dist & let er rip. Get the carb in the ballpark then the dist spot on then final fine tune on the carb. SCR= static compression ratio

Posted By: Erik

Re: Too much Carb?? - 11/25/14 01:44 PM

Compression ratio! Duh!

10:1

Posted By: terzmo

Re: Too much Carb?? - 11/25/14 02:20 PM

I think you'll be fine. Remember, they put a 990 cfm setup on a stock 340...or so they said it was lol

Posted By: Rob C

Re: Too much Carb?? - 11/25/14 04:44 PM

990 CFM? Never ever heard that one.
Stock TQ's are commonly refered to as 800 & 850 CFM units. The 340 had both on top. The largest Carter on top was a 630 AVS.
The 1250 CFM 6 packs in 4bbl. terms was a 780 rating.

Follow the above advice on the secondary air door. Tighten it up.

Posted By: dartgame

Re: Too much Carb?? - 11/27/14 01:01 AM

You'll be fine - Im using a 71 440 AVS on my 328 - (318 +060), mild hot rod. Runs the same as the holly street avenger I had on it before, except it does not chew through gas nearly as fast.

Posted By: terzmo

Re: Too much Carb?? - 11/27/14 03:31 AM

990cfm was on the 340 6 pak setup

Posted By: ohiodemon

Re: Too much Carb?? - 11/27/14 04:07 PM

go get a holley 750-800 dp carb. bolt it on and hold on that'll wake it up.

Posted By: Dean_Kuzluzski

Re: Too much Carb?? - 11/27/14 04:17 PM

If throttle response at low rpm, clutch engagement, and street drivability are what you're really concerned with............it may not be the carb cfm, which is a little big, but more of a initial and total mech. advance issue to push on the motor with all that .050 duration and mildish 3.55 gearing.

What is your initial timing? Total? And then mech. advance is what I'm getting at?

A slow/soft advance makes many a carb seem too big.

I'd tweak the mech. advance and if you're still not happy drop down to a 750, then 700.

Posted By: lewtot184

Re: Too much Carb?? - 11/27/14 05:20 PM

the total air flow isn't an issue; if you believe the advertised flow numbers. the issue for driving is going to be the large primary throttle bores/venturis, poor out of the box calibration and too large of an accelerator pump squirter. ignition recurve a must with that cam. it's all doable, if you have the knowedge/skills, but not ideal.