i had a family member rebuild my carb, everything was fine untill im going around 60 mph and it has an awful pinging, sounds like bb's in a can. whats the problem and how do i solve it?

Is this a computer q-jet, or non-computer? Stock or modified engine?

I'm not sure I've ever heard an engine ping at speed that didn't during acceleration.

its a 86 trans am stock engine

Is the SES light coming on?

Have you checked where the timing is set?

I put on another carb off a parts car of mine it it ran fine, its just a problem with the rebuilt carb

probably a piece of debree stuck in one of the cruise circuts