back fire??

[66StangGuy]

sounds like it could be a timing or timing advance problem.

have your changed your timing from its stock setting?

also check to see that it is stock or whereever the cam or other parts specify. i had the problem on my car with my timing was too advanced. it would hesitate for a second before it would take off and had small backfires while trying to start the car after it was warm.. tapped the timing down a little and the car starts perfectly every time and the hesitation is totally gone. what a big difference that made.