Chevy installed 750 cfm q-jets on 350 engines they ran fine. Holley ran an 850cfm carb on the '70 LT-1.
Edelbrock - which one? 1406?
Instructor
Joined: Nov 2008
Posts: 106
Likes: 1
I first bought a 1405 edelbrock but the person I talked to at Edelbrock told me it wouldn't pass emissions and I needed to go with a 1400 series. You will have to get the spacer to set that carb up to the intake, the square bore , spread bore difference. Another $50! It hooks up easy enough and runs great in our car. Easy to set up too. The guy we bought it from said it would not be friendly at the gas pumps, but my wife quickly told him it wasn't about mileage, 
. It looks good too.
. It looks good too.
Instructor
Joined: May 2008
Posts: 154
Likes: 3
From: Indiana
Le Mans Master
Joined: Apr 2006
Posts: 5,403
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well the Lt1s really had a vacuum secondary 780.
after 65 maybe 66 there was never anything chevy installed smaller then 750 cfm, mild or wild cammed engines.
327, 300hp very mild 195 .050 cam 750 cfm Q-jet.
I'm going to call some of the chevy engineers there could still be a few alive tell them I'm smarter then them don't you know 600/650
size carb is the answer.
after 65 maybe 66 there was never anything chevy installed smaller then 750 cfm, mild or wild cammed engines.
327, 300hp very mild 195 .050 cam 750 cfm Q-jet.
I'm going to call some of the chevy engineers there could still be a few alive tell them I'm smarter then them don't you know 600/650
size carb is the answer.
Last edited by Little Mouse; Dec 17, 2008 at 05:10 PM.
Le Mans Master
Joined: Apr 2006
Posts: 5,403
Likes: 95
the 283 chevy impalas had a bigger two barrel on them then any
250 cfm even though cam wise they run out of power below 4500
rpm
The reason a lot of fifties factory cars had two fours
there were not any big enough four barrel carbs available
to the factories to feed there hi po engines they really were not doing a good job ( single carb ) on there lo po engines. Back in the late 50s the 283 biggest four barrels around were 450 cfm' it would barely feed the base engine hydraulic cam 283, so when chevy used a litte higher rpm solid they used two 450 cfm carbs.
Last edited by Little Mouse; Dec 17, 2008 at 05:38 PM.
Drifting
Joined: Jul 2002
Posts: 1,944
Likes: 20
From: The only Corvettes in Highett Victoria
Big carbs and small engines
G'day,
Back in the early 80's, GM Holden in Australia fitted Q-jets to Holdens. Some cars had Chev 350s, the others had Holden's own V8, in 308 cubic inch (4.000" bore, 3.0625" stroke) and the "baby" V8 a 253 c.i. (3.625" bore and 3.0625" stroke. My original 253 Commodore used to get 30 miles per imperial gallon cruising.
For what it's worth.
Regards from Down Under
aussiejohn
8 months to go
Back in the early 80's, GM Holden in Australia fitted Q-jets to Holdens. Some cars had Chev 350s, the others had Holden's own V8, in 308 cubic inch (4.000" bore, 3.0625" stroke) and the "baby" V8 a 253 c.i. (3.625" bore and 3.0625" stroke. My original 253 Commodore used to get 30 miles per imperial gallon cruising.
For what it's worth.
Regards from Down Under
aussiejohn
8 months to go
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Le Mans Master
Joined: Apr 2006
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Square flange 650 front barrels 325cfm 750, 375cfm
can't remember a small block with less then a 350 cfm two barrel carb
to take off from a stop with things like a 2 speed powerglide.
either one at low rpms 650 or 750 is going to do a good job at low rpms if the engine does not use the full 750 cfm at higher rpms no damage done.
One of the more embarrasings things that happened to me I was rolling along in the 73 454 engine was big time modified had a 69 435 trypower on it, around 45 mph I was beside a 69 cougar eliminator I was going to tromp him. well the trypower that had always worked flawless let me down the center carb was 350 cfm outer vacuum carbs 500 cfm, the end carbs failed to open, my 454 is now desperatly trying to get air. bet the guy in the mercury is still telling about how he beat a 454 vette.
can't remember a small block with less then a 350 cfm two barrel carb
to take off from a stop with things like a 2 speed powerglide.
either one at low rpms 650 or 750 is going to do a good job at low rpms if the engine does not use the full 750 cfm at higher rpms no damage done.
One of the more embarrasings things that happened to me I was rolling along in the 73 454 engine was big time modified had a 69 435 trypower on it, around 45 mph I was beside a 69 cougar eliminator I was going to tromp him. well the trypower that had always worked flawless let me down the center carb was 350 cfm outer vacuum carbs 500 cfm, the end carbs failed to open, my 454 is now desperatly trying to get air. bet the guy in the mercury is still telling about how he beat a 454 vette.
Last edited by Little Mouse; Dec 17, 2008 at 07:29 PM.
Drifting
Joined: Aug 2008
Posts: 1,381
Likes: 11
The 1406 and similar AFB knock offs from E-brock are cheap and work ok on stock and nearly stock engines of 350 cubes or less. If you really have a performance engine and want to go as quick as possible the AFB clone won't get you there. Make a trip to your local track (drag or roundy round) and look what the fast cars are running. No AFB Edleturds.
Pro
Joined: Sep 2006
Posts: 551
Likes: 2
From: Clovis CA
I have the Torker II manifold, when the motor first went back together,I matched up with the Edelbrock 750cfm, It never ran just right, a little stumble, even my Tuner couldn't get it perfect. Put on the Holley 850 double pumper, it was like the heavens opened up and power rained down...But that's my car, maybe yours is different..
