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Author Topic:   Quadrajet JET sizes
Footlead
Dirt Full Roller

Total posts: 32
posted December 20, 2005 03:49 AM  
I have the Oreilley Quadrajet special for about 149.99 and it runs fine. The jets in it are 71's and it does seem like the motor wants more fuel so should I jet it with some 73's or what, or will I get more HP from the secondary rods and hanger being changed. Who knows about this subject?? The motor is a JR Motorsports shortblock with 441 heads, flattops cast iron intake with a sweet Lazer camshaft with alot of duration, but I may put a vacuum cam in it if I change classes. Are the 71 jets enough or not???? Thanks

Flying Jack Ace
Dirt Full Roller

Total posts: 30
posted December 20, 2005 05:24 AM  
Leadfoot

Might check with Bennet's garage. They are one of the best in our area with the Qjets.
I run BA rods in the secondary's. Are you sure the Lazer cam won't make 12" vacuum. You know they did away with the Lift rule altogether in both IMCA limiteds AND purestock...

KPLugnut
Dirt Forum Champ
Total posts: 1041
posted December 20, 2005 06:23 AM  
We build our quads typically with 72-74 jets in the primaries, with .045" primary rods, but we do MANY mods to the other areas that affect initial acceleration, such as power piston spring tension, secondary geometry, air flap geometry, secondary fuel feed circuit mods, air bleed mods, accelerator pump mods, etc.
In a nutshell, full race prepped quads are a LOT different than over the counter remans.

KP

Footlead
Dirt Full Roller

Total posts: 32
posted December 20, 2005 08:25 PM  
Thanks for all of the advice. The Lazer cam will hold 13 inches of vacuum but now they require 15 inches @1000 RPM aaaand .450 lift max. That Lazer cam does sound wicked though.. It hits hard.

Flying Jack Ace
Dirt Full Roller

Total posts: 30
posted December 20, 2005 09:21 PM  
Hummm I might need to talk to you about that cam. I't would be legal in here in waco. Here the purestock rule is 12" at 1200..

Footlead
Dirt Full Roller

Total posts: 32
posted December 21, 2005 07:53 PM  
The cam will pull 12 inches and your competition will definately hear it when you crank the engine. She sounds mean. Duration@.050 is 235/239, lift is .447/.447
Lobe center separation is 106. Advertised duration @.006=283/286. The only thing wrong with it is it aint cheap.

Flying Jack Ace
Dirt Full Roller

Total posts: 30
posted December 21, 2005 08:01 PM  
I know the one and the price...got the same recommendation couple of months ago...I didn't think it would make 12" without the anti-pumpups. I was'nt ready to spend $$ yet...

Howards makes similar spec circle track camshaft except its on a 112..I bet it might meet your rule...dont have any experience with it.

Jack,

This is the what to run. It's a synchronized package that will deliver the vacuum and power you need to be competitive. Upon purchase, I have a couple tips to help.

Camshaft: CS-H283C-286C-06 $164.29
@.050: 235 239
Lift: 447 447
Lobe separation: 106, with 102 intake centerline.
Recommended related parts:
Lifters: 8116H-16 special bleed rate 126.04
Springs: 913T-16 66.74
Retainers: 714T-16 52.80
Locks: 6011-16 heat-treated 7.09
Pushrods: 7016-16 heat-treated 31.54
Other vacuum rule tips available upon ordering
Cam Wizard

[This message has been edited by Flying Jack Ace (edited December 21, 2005).]

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