ACMESPEED

I have an unrestored (garage find) 1968 427/390 that runs and drives. Someone (prior to 84 when it was garaged) replaced the 427 heads with 454 heads and replaced the Rochester Q-Jet with a Holley 650.
(The Intake is original)

Since the (correct) Q-Jet carb is nearly impossible to find - I'm looking for a suggestion on a good alternate....keeping close to original until I can find the real deal.

Any suggestions on Make and Model # ?
Any suggestions on where I can find one ?

Thanks for any help
Mike

thegazman

"http://www.jetchip.com/JET_Carburetors.asp#BM3" Here's a Q-Jet 800cfm designed for a big block engine.

73, Dark Blue 454

I too like the Q-Jet for your 427. Whatever genius switched from the original 750 Q-Jet to the 650 Holley actually hurt performance, probably got worse mileage, and reduced the value of his/her Vette.

randommj

I say tri-power! have fun whyle you look for the "real deal"!

Miles

ACMESPEED

Maybe a dumb question, but will a tri-power setup fit under a Stock L-36 Hood ?

gbvette62

The stock 427 3x2 induction set up used the same hood as the 390. An original 400 or 435 intake is $2000.00 + item without carbs. I'll check tomorrow when I get to my shop, I think I may have a source for the 390hp Q-Jet, or at least, the GM replacement.

ACMESPEED

Perfect - Thanks

PRNDL

I bought an Edelbrock Qjet replacement for my 68 L-36. Part# is edelbrock 1901. I don't think they make them any more. There are many qjet carbs that will work fine on your car with a little tuning, and many numbered carbs that have nearly identical specs to the original Qjet that came with your vette from the factory.

sxr6

What numbers are your heads? 290s?? There's some indication GM may have started using these 70 454 heads on late build 69 cars?

Any quadjet from a pre 74 454 should work just fine on your motor unchanged. E-bay & a few other sources should produce a useable carb.

7T1vette

Q-jets have 750 cfm capability...the Holley you are considering has 650 cfm. And, as mentioned above, the Q-jet is a much better carb [flow, economy, smoothness of performance, adjustability......you get the idea]. Just rebuild it per info provided in Lars papers so that it is matched well for your engine. However, if you want originality or something just for 'looks', the Q-jet probably isn't what you want.

Jims66

Holley 800 or 850 cfm double pump. You'll Love it !!

sxr6

I question the originality comment ?
69 427-390hp engine all had quadrojet carbs as stock equipment.

RobRace10

I have the same issue and looking for a carb.

Here are 2 I 'm considering.

http://store.summitracing.com/partde...rsview=sku&Ns=

http://store.summitracing.com/partde...rsview=sku&Ns=

7T1vette

SXR6 is correct. I assumed the factory carb on the 427/390 was a Holley [without looking it up]. Heck, that's perfect! Keep the Q-jet.

IcemanZ06

he doesn't have the Q-jet, someone swapped it out for a holly 650.

I agree with the other comments to find a Q-jet. Original casting might be really tough but any 454 casting would work great.

thegazman

Rochester Big Block Q JET
Part #: 36003


JET Performance now offers a Quadrajet carburetor tuned for Chevy & GMC cars and trucks with 396 ci and larger modified big block engines. The carburetor is extensively reworked by increasing main well size and is balanced to assure top end high RPM fuel flow. Several circuit modifications are made to keep the fuel curve correct throughout the entire RPM range and to keep consistent idle quality. Includes a .149 needle and seat to ensure adequate fuel flow. The carburetor is designed for modified big block motors with a dual plane intake manifold, headers, 8.5-9.5:1 compression ratio and mild ported or aftermarket heads. Recommended cam specs: Duration @ .050 min 210 degrees, max 240 degrees and a lobe separation angle of 110-114 degrees.

Available as a complete unit or JET can rebuild your existing core.

800 CFM Quadrajet custom built for big block engines 396 ci and up.

onsturn

Both heads on my Nov 18th 69 Vette are 3964290 with a J27 9 date code on each. My book says J = Oct so they are both Oct 27th of 69. My LM coded block has a Nov 11th 69 date so everything seems correct. I am going to start a new thread about this issue.