Re: 70 camaro engine issue
I think Paul meant the float becomes leaky, and doesn't float anymore.
There is a problem with the marking some replacement GM and aftermarket balancers when used with an earlier timing cover tab; should be able to find the discussion here using "balancer mark timing". I used a current (at the time, 1999) 8 inch GM replacement balancer on the 68 327 in my 68, and had to remark balancer. The difference is something like 15 to 30 degrees, enough to really mess things up if not noticed. Timing would be way retarded. Someone unfamiliar with the change by GM of the 8 inch balancer timing mark could say that the balancer is bad, with the outer ring having slipped relative to the inner because the rubber is worn/bad.
That said, not sure your prob could be just timing. Could easily be idle mixture setting (did not say which 4bbl you have), idle speed, choke operation, wrong spark plug heat range or gap, bad plug wire... The list goes on and on.
69 'vert project big block/TKO 600 RR
68 'vert driver RS clone -- gone!