Quote:
Originally Posted by 2manyT/A'S
Well Mark,your post this morning inspired me to go digging in the "uncharted areas" of my basement & thought these might interest the HO guys.
According to the sheet they will ALSO work in the "other" round port 455 (2nd fastest) as well as any other 71-76 455.
As I understand it,a high compression round port 455 was planned as the ULTIMATE large displacement Pontiac motor for 1970 & I'm guessing GM comissioned TRW to design these pistons (perhaps as an OEM application),but with the premature DEATH of high compression engines for 71,there was NO OEM market for them.
One of our contributers here (from the Great White North) has a set of these in a 72 HO with the domes cut down to reduce chamber volume.
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These pistons are TRW L2394F. Not too rare or unusual. They may even still be available from Sealed Power, I haven't checked in a few years. I have 2 sets in my parts stash. They have grooves machined for floating wrist pins, and lock rings are included with a set.
They were designed to be used with 455HO and SD455 heads to give about 10.5:1 with a standard bore size. It was common to smooth the "bumps" from the domes to improve combustion efficiency. I believe HO Specialties marketed these pistons and recommended removing the "bumps."
I doubt these were a GM design, as all of the Pontiac high compression engines used smaller cylinder head chambers, not domed pistons.