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.

[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.....

[LEEVON]

Originally Posted by 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

Second that ocbaud.

Vern350, in case you haven't bought a carb yet, I think the Demon 650 w/ vacuum secondary would be a great choice. I used to be scared to death of carb tuning, mainly because I didn't have good luck with Edelbrock Performers. After I figured out how to tune the Demon, I'll never go back.

[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.

[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.

[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.

[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

[Ivan D.]

Pyro, the pistons always move freely when I installed them, I made damn sure of that. There was absolutely nothing down the bores that could possibly jam them, yet they always managed to get stuck after a longer drive - I was at a total loss on that one, never seen or heard of anything like that. Truck's gone now, traded it two months ago for the diesel I drive now, but I'm still stumped at what could have been possibly wrong with that otherwise brand new carb...

[Pyrotechnic]

Originally Posted by Ivan D.

Pyro, the pistons always move freely when I installed them, I made damn sure of that. There was absolutely nothing down the bores that could possibly jam them, yet they always managed to get stuck after a longer drive - I was at a total loss on that one, never seen or heard of anything like that. Truck's gone now, traded it two months ago for the diesel I drive now, but I'm still stumped at what could have been possibly wrong with that otherwise brand new carb...

I think I'm having a similar issue to what you were experiencing. I've been playing with the AVS a little bit, and sometimes when I gun it, around 4000 RPM it starts feeling short on power and revving slower. Other times it rev's to 5000 RPM quickly.

When I was reassembling the carb, I noticed one of the metering rods...the one that was jammed from the factory, took a little wiggling to get it to slide down and move freely. The other side in comparison was like butter, it just dropped on and felt smooth.

I'm gonna try and get to the bottom of this issue. I hope there really is something wrong or I'll be chasing a ghost.