That octane boosters are Bull$hit. *phew* I didn't want to say it out loud but i figured as much

I've checked my TDC marker and it was difinitly accurate or very close to accurate. I actually used the same method as you Dodgeman, only I thought I was really clever at the time when I thought of it

I think my distributors advance spring mightof stretched a bit causing it to advance to much. If its not that i'm going to throw in some warmer sparkplugs and see if that doesn't help aswell.

TA