Carburetor Selection

[vern350]

I posted a tread similar to this in the engine and drivetrain section and still not 100% on what carb I would like. Truck is going to be a weekend warrior. Motor is a 350 with 69 corvette heads with 2.02 valves. Has a 525 lift/248 duration comp cam in it. Compression ratio is 11.5 to 1. Has standard gears in it right now, I'm assuming 3.07 or 3.08s. Eventually will have 3.73/4.10s. Transmission is a turbo 350 with 2800 stall converter. Edelbrock performer intake.

I would think a Edelbrock Performer 1406/600 cfm or Edelbrock Thunder series/AVS 1806/650 cfm carb would be in the correct cfm range. Would like to go with an electric choke. Does this match my setup or is something larger needed?

[ocbaud]

i had the 650cfm avs carb in my truck when i built the engine. could never ever get it running great. finally upgraded to a 650 speeddemon and will never buy another carb again. i dont know why people complain about how hard they are to tune, it's way easier to adjust than the edelbrock i had.

that being said, if you're looking at the avs carbs, they are in the same price range as the demons

[Pyrotechnic]

I bought a remanufactured Edelbrock 600CFM 1405 and it's been running great. It actually run BETTER than some new carbs I've gotten from them.

I got a new AVS from them and it ran AWFUL. Turned out to be a bent metering rod, I guess because someone goofed on the assembly line. I never got to run it much after fixing it but thats an entirely different topic. It's been sitting on my garage floor for a year and a half now and I'll be giving it another try pretty soon.

[BowTieOgre]

A buddy of mine bought an avs and he could never get it to cooperate either...im seeing a pattern here. I bought an Edelbrock 1406 for my truck. This 600 cfm carb should be a good fit for a stock 350 with headers and an intake.

[nico]

I would check into a 650 to 750 vac. secondary Holley. I have a similar setup on my 383 and love the 3310 Holley I built for it.

[piecesparts]

Everyone has a good and bad carb experience. I have been running the Carter and Edelbrock carbs for quite some time. I have an AVS on my stroker motor and it handles it real well. The 650CFM is just aobut right for daily driving and still gives me some range in the upper end. A 750 would be to much to drive daily and get good performance, but the top end would be outstanding. A fuel injection system would be better but the cost is also bigger.

[454HO]

Since you have a Performer intake, you can directly bolt on a spreadbore carb. There would be nothing wrong with running a properly tuned Q-Jet. You'd probably get better fuel milage too.

But if you decide to use a squarebore carb, you may need to use an adapter plate to make sure it seals well to the manifold. I have seen many times where guys just bolt an Eddy carb onto a 'universal' manifold and then have drivability/tuning issues that are later traced to vacuum leaks around the base of the carb.

[babyJay]

Originally Posted by nico

I would check into a 650 to 750 vac. secondary Holley. I have a similar setup on my 383 and love the 3310 Holley I built for it.

On my '79 I'm running a 670 CFM street avenver, vac secondary, electric choke. Part #80670. Ran great last year, and I have yet to go to the mud pits this year. I hate the damn thing...

Thinking about an Edelbrock 600 myself.....

[Pyrotechnic]

It strange that I'm hearing so much bad news about the AVS. I have a feeling that someone was seriously goofing up on the assembly line.

I have a hard time believing there's anything wrong with these carbs by design because they are basically the same thing as the tried and true AFB, except they have a spring loaded secondary door instead of a weighted door.

I only wish they made them in the 750 CFM flavor. 650CFM is too small, 800 CFM is too big...at least for a 383.

[84 400]

Got a 650 CFM Eddy on mine and have no issues what so ever. Great carb thus far and I like them more then the q jet i had on my 85 c10. Not saying the Q jet is a bad carb at all. I would keep lower then 700 CFM if your planning on daily usage or weekend for the best balance between fuel and preform acne

Mine is about 5 years old now and is a weekend driver not a daily

[vern350]

thanks for the replys. I guess i stay away from the AVS carbs. Still not a 100% on what to choose between 600cfm and 750cfm perfomer carbs. I'm thinking 600cfm, but its not going to be daily driven. Strickly weekends.

[vern350]

OK, 600 CFM will be the winner. Should I stay with my manifold? It is the universal performer manifold with 8 holes. I couldn't see a parts number, checked between the carb and the dist. I'm assuming 2101.

[piecesparts]

Originally Posted by vern350

thanks for the replys. I guess i stay away from the AVS carbs. Still not a 100% on what to choose between 600cfm and 750cfm perfomer carbs. I'm thinking 600cfm, but its not going to be daily driven. Strickly weekends.

I would like to hear more aabout AVS problems, the only difference in these carbs, is the addition of the adjustable butterfly on the secondaries that is not there on the 600 CFM models. As I said, mine is working real well and the added CFM flow rate is a good combonation for my driving. The 750 was too much for drivng on the street, with the cam combo that I have.

[chev74]

you wont want anything over a 670 cfm on a small block. too much gas flowing even wit your 11.5 compression... thats my .02

[slugish]

Quite a large bumpstick for a 600 cfm carb. Any headwork or alum. perf. heads? that would make a large difference in deciding carb size. If you have stock heads , aggressive cam &carb over 600 cfm is not going to do you much good. Cam should be matched to heads & carb matched to those . ,

[Roper]

I have a 650 avs on my sbc DD and it works perfect. Been running it a year or two now. Real easy to tune/ work at.

[jchav62]

I run an Edelbrock AVS 650 on my '62 with a Performer RPM intake and a Summit 224/224 cam on a 327. Great combo! I drive it almost daily with no problems...

[75sierraclassic]

I would upgrade your manifold to a Performer RPM or Air Gap. Here is a good article on manifolds.

http://www.hotrod.com/techarticles/1...mbo/index.html

[larry may]

DORFS AND Mopar like them AVS carbs. Chevy never did. lol

[vern350]

Originally Posted by slugish

Quite a large bumpstick for a 600 cfm carb. Any headwork or alum. perf. heads? that would make a large difference in deciding carb size. If you have stock heads , aggressive cam &carb over 600 cfm is not going to do you much good. Cam should be matched to heads & carb matched to those . ,

Engine has 3970126 69 heads with apparently larger 2.02 valves. I should be able to bolt a performer carb on my intake without any problems, correct?

[slugish]

Originally Posted by vern350

Engine has 3970126 69 heads with apparently larger 2.02 valves. I should be able to bolt a performer carb on my intake without any problems, correct?

correct, 650 cfm with vacuum secondary would probably be max for your saet up .

[vern350]

thank you slugish and thanks for the replies.....slowwwly piecing all this engine stuff together. Rookie at it, but its coming.

[Pushrod226]

I second that 3310 750 vacume secondary. Excelent and very overlooked carb for souped up small blocks. Other great carbs that're very overlooked are Holleys spreadbore carbs. GM didn't use 750 cfm spreadbores for no reason. Holleys are just way easier to tune.

[Pyrotechnic]

Well I picked up the AVS off the floor and decided to give it another shot.

I cleaned it up then pulled the top off to make sure everything was cool. One issue I ran into was the bent metering rod right out of the box, and upon pulling the top off I found something else wrong. The float drop distance on one side was way off. The up position setting was in spec for both sides though. I'm not sure how the float dropping down too far affects things, but none the less it was wrong according to the Edelbrock manual.

I pulled off the AFB, put on the AVS, fired it up, set the idle speed and mixture, then drove it. It drives just as well or better than the old AFB, except in the upper RPM ranges but I haven't even adjusted the air door for the secondaries yet. I think it's set too stiff because once I get to the 3000+ RPM range, I'm not picking up speed as quickly.

[Ivan D.]

Originally Posted by Pushrod226

Other great carbs that're very overlooked are Holleys spreadbore carbs. GM didn't use 750 cfm spreadbores for no reason. Holleys are just way easier to tune.

Oh yesh, 4165 Holley is what I had on my truck, that thing could run from Detroit to Ann Arbor at triple digits on just 3/4 throttle, and I could still cruise at 60mph on 1/4 throttle and get 20mpg on a good day! The 4165 is a double-pumper carb with two power valves, if anyone wants to get one of them make sure tis an old unit with a roller secondaries linkage, as on them you can adjust the opening point of the secondaries between 1/4 and 3/4 throttle, can't do that on the newer short-link models. Takes a bit of time to get the right combination of jets and power valves and secondaries opening position, but once there it just hauls

Edit: I had a 1406 Edelbrock on my 429 big block, that one just pissed me off, the power pistons would get stuck at random times so I would ent up with half my cylinders running lean, or rich, or both, no pattern to that whatsoever either. Tried even greasing the pistons, helped for a bit, but on a longer drive the heat would eventually melt the grease and the pistons would get stuck again - anyone had that issue with an Eddy carb? It was a brand new unit by the way, not a used and abused one.