Originally Posted by Kerry W
10:1 is certainly 'adventurous' on 92...I'd have expected not more than 9:1 and probably more like 8.5...
'Competition' Gold Stars came with 10:1 pistons and when I rebuilt the engine 25 years ago just about every station carried high octane fuel so it wasn't a problem. Now it is.

If it worked as advertised the Lucas octane booster I used increased the octane to 95. Since the engine still knocks at 95 it needs more octane than that. Eight oz. of the stuff that's on its way to me now will increase it to 100 and, if that's not enough, 12 oz. is supposed to be good for 104. If it still knocks with 104 then rebuilding the engine as a side valve may be my only remaining option...