I have 64.5 mustang D code 289. I have had this car for about a month and the motor was rebuilt about 5000 miles ago. It's hard to start but once it is started its sounds good. After a few miles at a light when stopped it will want to lunge forwars. I really have to stand on the break. I'm thinking timing? What could it be. I was going to get it a tune up soon but wanted to have an idea of what it could be.

Thanks

 

I'd look at timing first, easy enough to set with a timing light. Next I'd look at vacuum leaks and how clean is the carb, did it sit up, float bowls set at correct level, fuel filter fresh?
Jon