[Walt Fricke]

Well, I ran it up to 8,000 or so (EGTs and AF looked OK), and then backed off and started a recorded run. Some way into that run (I think we were using 4th, looking to start at 4000 or 5000, and don't recall if I had gotten to 4th or not) I got the shut down signal from the dyno owner and my wife. Smoke out of the right rear megaphone. After shutdown, oil dripped out also.

After this happened I recalled the buddy who had it happen to him on two engines in a row at the track.

The pin boss (if that is a suitable term) is only about 4mm wider than the pin, leaving 2mm per side at the pin centerline to hold the forces trying to yank the cylinder down during the intake stroke. The pin does not extend out beyond this part of the boss - the groove for those horrible clips is right at where the skirt part starts.

I'll have to check to see what pins I have - whatever came with it.

These pistons, after I had them recut for larger intakes, and again to get enough valve clearance, were 12 to 1 CR measured, on a 66mm stroke with 3.2 heads. I'm debating going back to 10.5/1, but CR didn't seem to affect this. No signs of detonation. Nothing special to indicate this was caused by this piston sticking up around TDC. Top two rings look pretty good, considering (lands a bit compressed in spots, so they don't want to slip out