I have a 94 LS block with a 95 GSR head. Did a first start up about a week ago and the car runs great. Tried to adjust the timing and it seems that it is firing at the TDC mark (white notch), and not the 16BTDC mark (red notch). I adjusted the light to 16 and it moved the TDC mark far from the timing mark on the belt cover (negative timing).

Car runs great through all rpms. No popping or cutting out. Checked my timing belt job about 30 times now and everything lines up perfectly, and belt is tensioned to spec. Adjusted the dizzy, but it wouldnt' go anywhere near far enough to fix the problem.

Found a few posts on the net about it, but no definitive answer. Any suggestions would be appreciated. Thanks.