Stovebolt.com Forums The Shop Area The HiPo Shop Weber 32/36 carb jetting?

Yes, switch the carburetors and see what happens. Also is your vacuum steady, wandering through 3 or 4 pound sweeps or jittery? A compression test is a very good idea. Good to put your mind at ease. Check also both accelerator pumps. Good on the ported vacuum. Personally I'd hook vacuum back up to the distributor. I know there are folks who'll say you don't need a vacuum advance with HEI, but I'm not in that group. Very lean condition in addition to burning slowly can burn unevenly and that will also cause backfiring as rpms increase (won't all burn before the next intake stroke occurs). Good luck!

I GOT IT! I GOT IT! I reset the timing by the old 59 235 spec, reset idle speed to a little less than 500rpm. I have a analog tach, so, the manual calls for 475rpm. I would have to get a digital tach to be more accurate. Re-attached the vacuum advance to the distributor, cleaned carbs and checked jetting. It runs PERFECT! Lots of power and no spitting or backfire. Thanks for the suggestions and help.
Compression is 135- 140 on all cylinders by my Matco gauge.

That's great and happy to hear it. Timing, valve adjustment, etc can make a big difference in these. Now just a matter of enjoying it, eh?