I have a bigport metra that has been seized a few times it has been gps'd at over 65 after being seized but has pretty low compression now. you could clean it up a bit more and get some better compression out of it or maybe replace the rings or the piston
it has been ported and has two oiling holes in the piston on either side of the exhaust port (if they help I'm not sure)
its still on the bike so I can take it off if someone is really interested in buying it and send you some pictures but basically it looks like a metra that has been seized
I would like $135 Shipped for it I will include the head, cylinder, piston, rings, wristpin, circlips, and base gasket