the timing is right and the firng order is right a guy that worked on it said he thinks it has something to do with the distributer cap
i have a 1975 pontiac firebibird starts and runs but runs real ruff on 1990 Pontiac Firebird
Which engine you got? 4 options, some had the inline 6. Then all the way up to the 455!! IF it is an 8 cyl.,that old Rochester Quadrajet carb. would be a good place to start looking! Manually choke it and see if that helps. A good cleaning, BRASS float, needle and seat will fix 95% of them!
its a 400 30 over and the carb is newly rebuilt the motor was running good and the guy kept tweeking it and one day it was running great and the next it just sounded like it wasnt hitting on all 8 he thought it mite be somthing to do with the distributor timing is good and the firing order is right i dont know what else it could be