Rochester Quad-jet advice

[royale 75]

Having owned GM cars for almost 30 years, I've seen a bunch of Quadrajets. Luckily, they've all worked reasonably well and so never been in one. I have, however, heard horror stories of their difficulty to rebuild, to the point folks swear its not even worth trying. I've done plenty of one a 2 bbl carbs and most of these were Rochesters - no problems, always successful. I'm poised, kit in hand, ready to go on my '75 and thought I'd inquire before I commit. Any advice?

[Sgt Art]

The rebuild kits are pretty cheap ($20 +/-) and a pail with parts strainer bucket inside carb cleaner isn't that much either (it's a good thing to have even ifyou don't build carbs). I've done a couple and if you work slowly and have reasonable "take apart and put together" skills, you can do it. Doug Roe has a book that shows all of that which you should be able to find at most parts stores. It can be difficult. One thing that happens, is the throttle shafts wear out the throttle plate (thin bottom piece) and that creates vacuum leaks and some slop in the throttle. Specialty shops bore those holes out and put bronze bushings to fix that. It can be done at home, but is a bit tricky and best left to the guys that do it regularly. I point this out, because you could do a good rebuild and still have a rough idle.

I found the Edelbrock (Carter) replacement squarebore carb to be a fast, easy replacement. Works great on my 455, very streetable and easy to tune.

[Guest]

I'd agree that they really aren't too tough. I've had Q-jets apart many times in the past 8 years.

In addition to the throttle shaft bushings, the other problem is the "top" of the carb, or the "air horn." I'm talking about the top piece of the carb about 1/2" thick that you remove to work on the carb. MANY people will overtorque the long front bolts that hold the carb to the manifold. This will bend and warp the top of the carb, and create gas leaks and sealing problems. Be sure to check yours out when rebuilding, as a warped top is very difficult to use on a carb and not have problems. Some specialty places will straighten the top for you, or you can search for one from a different carb.

Good luck.