The 6 bolt pistons that ipd had made several years ago were a teeny bit larger than the more common B21 piston retrofit. Unfortunately, I don't have any of the specs handy for either variety. What I wonder is this: is it possible that there's a headgasket that's suited to the (slightly smaller) B21 piston that would happen to be slightly too small for the (slightly larger) ipd 2200cc piston?

About the only idea I'd have would be to sacrifice one gasket by installing and crushing it; then hand turning the engine through a couple revs, then disassembling it for inspection. This *might* tell you if the piston is contacting the gasket (and it might not); but it _won't_ tell you whether the piston will or will not contact the gasket when the engine is running.

I guess my short answer is: I'm not sure. If it were me, I might check with ipd and see if they can offer some comparative measurements.

Best,

Cameron
Rose City