this Ross piston had an excessive expansion problem. had to give it some good hits with the hammer to get it out of the cylinder. 0.006 clearence just wasn't enough. when we boiled it in the pot for 5 mins & measured it it grew a whooping 0.009. all the rest only managed 0.0035. the build date on these were '89?, i'm sure they're good these days but i'm one of the "once bitten ..." crowd. i gotb KB's now. great piston in my books.