Another Q-Jet question from Bee Jay
Thread Starter
Safety Car
Joined: Nov 2005
Posts: 3,961
Likes: 573
From: Lompoc, CA. Santa Barbara County
17059228
0729 CBU
Primary 1 3/8" bore, =72= stamped on the jets, 42k stamped on the rods,
Secondary 2 1/4" bore, BE rods, F hanger
But the carb has been modified significantly. Brad Urban, a Quadrajet guru of the '80s had it last. He enlarged the primaries to 1 3/8" and enarged the accelerator pump to use a Rochester 2 barrell pump, and lots of other mods. See this thread:
http://forums.corvetteforum.com/show...ight=Quadrajet
0729 CBU
Primary 1 3/8" bore, =72= stamped on the jets, 42k stamped on the rods,
Secondary 2 1/4" bore, BE rods, F hanger
But the carb has been modified significantly. Brad Urban, a Quadrajet guru of the '80s had it last. He enlarged the primaries to 1 3/8" and enarged the accelerator pump to use a Rochester 2 barrell pump, and lots of other mods. See this thread:
http://forums.corvetteforum.com/show...ight=Quadrajet
Last edited by Bee Jay; Jan 5, 2007 at 12:30 AM.
Thread Starter
Safety Car
Joined: Nov 2005
Posts: 3,961
Likes: 573
From: Lompoc, CA. Santa Barbara County
Yep, more than a few people told me that my primary jets were too small. I tried larger and ran way too rich. Now I'm just a little to lean at no load coast, idle, and small load. I need to find some smaller rods. The place I bought my other stuff only list early rods, but say that they will work in later Q-jets with slight modifications. What would that be?
Safety Car
Joined: Dec 2004
Posts: 4,071
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From: San Diego CA
Hmmm.... 40k... I think I have a set of 41k. It'd be hard to find a set of 40k rods, that's for sure. You'd have to call a bunch of old school carb shops and see what they have. I think to use old style rods you have to bend the hanger enough to drop the rods lower, because the older rods are shorter.
Tech Contributor
Joined: Aug 1999
Posts: 14,380
Likes: 6,391
From: At my Bar drinking and wrenching in Lafayette Colorado
The difference in early and late rods (up through 1974 versus 1975 and newer) is the length of the rods. The early rods are about .070" longer than the late rods. It's possible you could bend the power piston hanger arms upwards .070", but I haven't tried this to se if that will cause the hanger arms to hit the bottom of the airhorn at WOT and limit your WOT mixture - you'd have to check it.
