I have a factory five Cobra replica with a CHP 347 Edl. rpm heads and intake 274 Comp cam etc. The car went 11.70 117 on a 1.79 60 first time I had it out. I recently went to a rpmII intake and a set of M/T 26x10x15 slicks. My 60 went to 1.57 and my et went to 11.62 while my mph dropped to 115.6. What happened? The temps were almost identical on both days, if anything the air was better the second time out. I played with the timing and it seemed to like 36* total the best. Any Ideas?