I have light springs in my MSD distributor; my theory being less torque at low rpm.
Yes, replacing the broken spring solved the problem;

thanks very much.
Saturday was cold and wet; I did a 360 coming off turn 5, running in 4th gear; stayed on track; lucky! Running slicks (BFG R1) for the first time this year; having trouble with them on cold/ damp surfaces. The Porsches had an advantage.
Really good on warm days. Sunday was much drier; reeled them in, running the whole track in 4th gear; no replacement for displacement. Fun running with GT2s and out running GT3s on the straights.
Car is good; driver has lots of room for improvement.
Jim