I am not really sure where to begin because there's a lot going on. I got my car back yesterday after getting the carbs rebuilt and it ran so much better, however that all changed. I deiced to take it on the highway to see how it would do. It did well, but when I got off and headed home it got bad. At a stop light it idled rough a few minutes later I noticed that the spedo would not go above 30mph (I was in 4th gear). At another stoplight As I shifted it into first it struggled to get going and then picked up after putting my foot down further to the floor. Finally I was a few miles from home after sifting it into second the engine backfired. I had this issue before, but that was fixed after discovering it was a bad set of points causing the backfire. Also the backfire sounds a lot louder than before.