Acutally, I was interupted and hit the submit button before I was finnished with the post. I am going to rebuild my "spare" engine this summer but had a problem with my "running" engine and needed to do a quick repair. I found a piston that the rings grooves had blown out and just the oil control rings were left. Luckly the Cylinder looks fine inspite of it. It was an AE brand and the engine had been rebuilt before with a Higher compression head. I was Talking to the guys at British Parts North West and he said that the difference is between parts designed 40 years ago and parts designed recently. The AE pistons are original parts and the Countys are a newer design. He said that the County piston rings seem to hold up better with higher compression than the AE. If this is so, then my piston was a good example. Anyway, Obsolete Automotive up in Canada was able sell me a single piston rather than a whole set like everyone else. It is a County piston. They also had AEs. The County is $60 and the AE are $117. I know, I know! I should match the pistons and balance them and all that but since this is a temporary fix while I rebuild my "spare" properly it not a concern. I actually drive my TR and really want it on the road.