Rochester Carburetor Question

Hi,

Might try a new gasket if you haven't already.  Try gasket sealer on the new gasket.  New throttle plate maybe.

Or if the warp isn't too bad, you could wet sand on a surface plate or other very flat surface.

Pat, perhaps others will chime in but I haven't heard many instances of the base plate of a Rochester 4bbl warping. Usually it's the air horn (top section) of the carb that warps due to over tightening. One thing that I am aware of, specially with 4 speed cars, is a vacuum leak in the base plate were the primary throttle shaft goes through the plate. There is no bushings of any kind in the base plate and over time the shaft becomes sloppy, causing a vacuum leak. this may or may not be a contributing factor. The sloppy shaft can be repaired with a bushing kit available from several vendors. Check out Quadrajet.com or do a search for a guy named Cliff Ruggles, both will have just about every part you need for a Qjet. Now if indeed your base plate is warped, it will have to be machined flat or replaced with a new or good used one. You might also try replacing the gasket between the carb and manifold along with the gasket between the base plate and the fuel bowl (center section) of the carb. A new set of gaskets may be enough to compensate for minor warpage of the base plate. Good luck, hope this helps and let us know what you find.

Thanks for the reply I've tried new gasket already will have to keep looking thanks again

Thanks for your reply I will check out the info you sent me and let you know what I find Thanks Again

You can check the throttle shaft bores by limiting the spray at where they go through the throttle plate. I successfully redid the bores on my friend's Holley on his '66 big block roadster using a kit that included a reamer, bushings, and instructions. The hardest part was removing the screws for the throttle plates which had been peened over at the factory.

Thanks for that I will look into it and keep you posted

Base gaskets are prone to burn-out around the secondary throttle blade area. The section of the gasket is quite thin in that area, and the heat from the EGR crossover will burn them. Check the gasket first, and go from there.

Thanks for the reply will update post as I go

Hello All, Please follow Joel's suggestion and then go to Quadrajet carb website and get a new base plate which will have all new bushings etc. Over the years I have had to bite the bullet after many attempts to straighten or level the base plates.I could have bought a new carb for what I spent on trying to fix the plate,and time lost.