Well, I think I've got it!! We changed the coil, tach, tried 3 different MSD boxes, checked fuel pressure. We ran the 306 on Sunday and it would only rev to 5,200 rpm. After 4 runs it started making valvetrain noise, nothing serious, but still noise. Anyway we thought it might be the valvetrain floating so we pulled the heads tonight and everything looks a-ok. Then I learned that the cam was a hydraulic piece and the rest of the valvetrain is roller. The motor has been assembled for 3,000 miles (we did not build it), and the cam looks pretty worn. I think that after we put a roller cam in it, we should be good. If not, we may be losing fuel pressure at the high rpm's. We are going to hook a guage up and see. Will let you guys know.......