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Old 07-03-2007, 10:12 PM
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Carb size and choice

I have a 79 camaro with a 355 we have set up for some budget drag racing. The car has a 4:56 rear end a th350 with a shift kit, roll bars tied into subframe connectors, 29 x 10 slicks and comp eng traction bars. The engine is a stock bottom end cast piston 9.5 comp votec headed engine, running a 270 magnum cam a summit stage 3 manifold pro billit crane hi 6... we ran a 8.21 second 1/8 th mile with it I want to get to the 7 second range right now we have a 600 edelbroc on it I have a 750 eldelbroc a 750 vac sec holly and a 750 quadrajet what would be the best choice for this set up .

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Old 07-04-2007, 11:10 AM
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Just did some reading on this the other day. From what I have read not personally experienced and from what a couple of ole school draggracers have told me that the Holley 750 double pumper mechanical secondaries is the best for the strip, the edelbrock performer best on the street with better tip in and fuel milage, with the Holley vac secondaries and Q-jet coming in last. I have the edelbrock 600cfm on a street car gets 18 to 20mpg,on 93 oct, it just isn't great outta the hole but does run strong on the interstate. Brian
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Old 07-04-2007, 11:23 AM
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Thanks for the reply Brian, The 600 in mine is the electric choke version which I think is economy calibrated, I had the edelbrok 750 on it but it seamed to idle rich I wasnt familiar with the idle circut on them it appears that it is separate from the rest of the carb so maybe I didnt adjust it correctly I bought a vacuum guage maybe that will help.
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Old 07-08-2007, 12:20 PM
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When I adjust the mixture (engine at operating temp and timeing and idle set) I usuall start out with the mixture screws 1 1/2 to 2 turns from bottomed. then adjust them till I get the fastest smoothest idle. The vac gage should get you dialed in.Brian
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Old 07-08-2007, 01:48 PM
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Quote:
Originally Posted by KGRIFF
Thanks for the reply Brian, The 600 in mine is the electric choke version which I think is economy calibrated, I had the edelbrok 750 on it but it seamed to idle rich I wasnt familiar with the idle circut on them it appears that it is separate from the rest of the carb so maybe I didnt adjust it correctly I bought a vacuum guage maybe that will help.
That 750 might be a little too much unless you are running awfully high rpm's.
The idle circuit consists of the metering rods and primary jets. After that the air bleed screws are the only adjustment. I have been running Edelbocks for years. I usually jet down until I get a lean stumble and then jet up one size. The Edelbock manual has all of the pertinent info on setting it up. You can go to their website and download it if you don't have one. Having a gas analyzer would make the job a lot easier.
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Old 07-09-2007, 09:01 PM
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i PUT THE 750 EDELBROC on we took it to the strip and it ran .1 slower but the temp was 95 and it was humid it didnt seem to rich and ran fine we are going to take it to the night races for better air and see how it does. My dad brought up a point that I am not sure it is valid or not but he was thinking because we took the wheel wells out and are not running a hood scoop it may be sucking air from the carb at the track end maybe that will be the next thing to try....
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Old 07-09-2007, 09:28 PM
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A 650 double pumper with a good 3500 converter would be my guess, ot the 750 vacume secondary carb. What stall converter are you running? What rpm are you shifting at? Dished pistons?
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Old 07-10-2007, 09:56 AM
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The Edelbrock is a good all around simple bolt on and go replacement, but it is not that good of a performer. If you are looking for lower et's at a track you need to rethink your carburation.
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Old 07-10-2007, 09:56 AM
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Quote:
Originally Posted by KGRIFF
i PUT THE 750 EDELBROC on we took it to the strip and it ran .1 slower but the temp was 95 and it was humid it didnt seem to rich and ran fine we are going to take it to the night races for better air and see how it does. My dad brought up a point that I am not sure it is valid or not but he was thinking because we took the wheel wells out and are not running a hood scoop it may be sucking air from the carb at the track end maybe that will be the next thing to try....
You never know. Kinda why nascar set there intakes up like they do, you'd be surprised what air does at higher speed. Brian
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Old 07-10-2007, 10:38 AM
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Hi KGRIFF,
I was watching horse power tv one weekend &
the young guy was running a Nova, & it was breaking up
at the other end of the strip, there was an older drag racer
there that said just what your dad said, "air is sucking
fuel out of the carb"., & that he needed to put something
in there to stop the turbulences, I don't remember what they
did to straighten it out though.
Take care,
rich
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Old 07-10-2007, 05:26 PM
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Quote:
Originally Posted by baddbob
A 650 double pumper with a good 3500 converter would be my guess, ot the 750 vacume secondary carb. What stall converter are you running? What rpm are you shifting at? Dished pistons?
This may sound kind of bad for building an engine but we just wanted to test the car a little before putting in a 406 we have, the engine is a 350 we bought for $75 because it had thrown the damper, my 10 year old and I tore it down replaced the crank with a used polished factory crank honed the cylinders out by hand replaced the rings on the cast zollinger pistons .040 over dished plus .045 in the hole steel shim .015 head gasket, bought a set of $200 vortec heads from the junk yard ported the exhaust (thanks to this site for help) ground down the retainers for clearance stiffer springs stock rockers used comp 270 magnum cam summit intake flow tec headers. Stall is suposed to be 3500 but it seams more like 2500, th350trans with shift kit 12 bolt 4.56:1 read with 29 x 10 slicks shifting at aroud 5000 to 5500. Ill try to post a short camera clip of it going down the strip. [IMG][/IMG]

Last edited by KGRIFF; 07-10-2007 at 05:37 PM.
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