We recently acquired a 1972 QJ for the project car. I have heard that people have gone into the nines with a single QJ. With work on the carb, how hard is this. Just went through a carburetor lesson today, pretty interesting piece.
First and ONLY tip I can offer: Read Doug Roe's book on the Rochester. Contains most of the mods available for a Q-jet, lists how to select parts to work with the Q, has examples of why things work on this carb etc. Definitely worth the read, and the $30.
Here is a lengthy, but very good read on Q-Jet tuning - courtesy of the MTS Caddy site.:TU: I'd second the comments on the Doug Roe book - consider it a 'must have' for your bookshelf!!:bglasses: :TU:
You mean the book that sits on the kitchen table at my Dads house. Looks to be a very good book, thanks for the reply.
Take a careful look at the air horn and main body gasket surfaces. I've seen WAY too many q-Jet carbs ruined by over torquing the front two carb-to-manifold bolts, compounded by "soft" carb base gaskets. On the really bad ones, you can see the warpage with bare eyes.
Steve, A properly set up Q-jet will not be a retriction for your quest to enter the nines. I have NHRA/IHRA Super Stock customers with small block Chevy's that run in the 9's regularly with a Q-jet. Most of these guys leave with the front end way up in the air and can trip the 60' clocks with the rear tires. Your overall fuel delivery system must also be addressed in order for you to keep the small bowl area supplied with fuel on runs that fast. As mentioned above, the Roe book is a good resource to have, but don't expect it to have a recipe to fully race prep one of these carbs. That's not to discount his book, but to blueprint a Q-jet for drag racing goes beyond what that book covers. In short, other issues will be more of an obstacle to achieving those times: horsepower (obviously), suspension/traction, vehicle weight, etc. Let me know if you would like to talk more about the carb and fuel system. Good luck! Dean Oliver www.holsfan.com/deano
