I have been trying to figure out a problem for the past two weeks to no avail. I have a 66 chevelle with a 283 and a 200-4r transmission. On my maiden voyage, when I put the 200-4r with B&M shift kit in gear the car chugged a little and backfired through the carb when i tried to accelerate. The car ran great in park. I retarded the time to keep tha car from backfiring, but now when I put it in gear, the car just barely runs and if you let it go for long enough it will eventually die. I have read every post on this websight and the monte web site that deals with timing, vacuum advance and rochester carbs. I have tried everything that I can think of and nothing seems to work. The car has an GM HEI with a new coil, module , spark plugs and wires. The Rochester q-jet was rebuilt and I checked all of the measurements again yesterday. The car won't idle reliably below 850 RPM and i have replaced all the vacuum tubing and put form-a-gasket on the base gasket to ensure that it was not leaking.

I initially had the vac advance set up on manifold vacuum and couldn't get anywhere. I switched it to ported vac and it is now better but it still lugs considerably when put in gear. I disconnected the lock-up torque conv. TCC solenoid after I replaced it to rule it out.

I have checked top TDC twice and it is right on. I have pulled all the vac lines off and plugged them one at a time to eliminate them and still I am at the same point. Idles pretty smooth at 850 RPM, put it in gear and it chuggs. The car backfires on startup at 10 BTC initial. I had to put the initial at 18 BTDC just to get it to idle smoothly. It runs good right now in park but the timing is way up over 45 BTDC total.

Where do i go from here?

Clyde

If it wants to idle at 18 deg before, and that setting gives you 45 total, I would retard the timing more. Set it to 36 or so total, and then plug in the manifold vac advance again. This should give you back some of the idle timing after you manually retard it. It sounds to me like you have too much timing in the mid and upper end.....knock the whole thing back 10 deg and give it a try. Then reset the carb idle speed and mixture. Good luck!

chris

38 Clyde, you havent told us much about your engine...is it pretty mild or do you have beefed up?
Either way it sounds like you are too lean.An easy way to check at idle is to put a rag over the carb (do it a little at a time) and see if it picks up rpm.If it does it is too lean. Does it run ok at higher rpm? The backfire on accel sure sounds like it is lean...does the accel pump work ok? also try a vacumn gauge to get a reading..and as for timing it depends on what type of advance system you have ..but 38 degrees total or somewhere close should make it work..
Steve