A better coil makes a lot of difference. I got a accel , the big yllow coil, the name is, super coil by accel, and it starts faster, stronger, has better spark at all speeds.I also have a 32/36 in my A15. I also noticed that area to be grinded, I will do it upon taking the head out for some valve and port work. I noticed, though, that if I am to make the manifold as big as the adaptor's opening,then, there is going to be very little manifold wall left. How far can I go, how much is too much, I think that the change in response will be noticeable, there is , right now a part of the stock manifold that hinders flow.