Hot Rod Forum : Hotrodders Bulletin Board - View Single Post - lighter forged pistons (KB vs speed-pro) worth $325 on a chevy 454
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Old 05-18-2011, 07:24 AM
MouseFink MouseFink is offline
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thin rings

People can get away with running the thin, low tension rings in engines that are driven daily. In fact, I had Pontiac 455 engine with factory SD pistons (TRW) and SD rods in my 1962 Pontiac Catalina. The factory 455 SD pistons had 1/16" top rings and that is one of the reasons the 1973-1974 Pontiac 455 Super Duty engine production was cancellled by GM. That engine could not meet the 1970 Federal emissions standards. The 1/16" rings in the 455 SD Pontiac engines were not used as weight savings but as an effort to reduce long stroke thrust loading and heat build up on the 455 engine's cylinder walls. The 455 SD engine was a odd-ball engine that tried to get past Federal emissions standards but failed. GM fired the two engineers that designed that engine.

Anyway, be advised of the problems associated with using light weight pistons in an engine for a daily driver. Wieight of the pistons is not the problem, but the other issues are. If you can find light weight pistons with standard tension 5/64" top and seocnd rings with pressed in pins they would be the ones to use in a street driven engine. Pressed in pins are heavy. Light weight pistons use thin wall light weight pins because they do not have to be pressed in a rod.
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