I am having a problem with my 65. I just recently replaced the coil along with battery and starter relay. Now when my RPMs reach a certain point the car begins to backfire and this happens in every gear as well. I had two other buddies of mine look at it who know a good amount about classic cars and they thought it was possibly something in my carb. They said they had heard of something in Holley's called a power valve and thought it could be that. If anyone could give me some ideas of what they think it could be it would be appreciated.