I put perfectly fine running double hump heads and a fresh solid lifter 30-30 cam with a Edelbrock performer intake and a Holley 650 double pumper. I’ve taken it apart and back together a few times now and still no luck. Timing is dead on I’ve triple checked installing the timing gear and can’t keep from back firing out of the carb to save my life. Put on a stock 2 barrel intake and carb and was able to run but not idle due to bad carb. My guess is my intake is warped.