L72 Piston Number Question

[Guest]

Hi All - just bought a 1967 (K15 dated) "321" 427 engine. With the oil pan off I can see dimpled rods and GM/TRW Part number 3888304 stamped on the back side of the pistons. Can anyone confirm the compression ratio and if these are for standard bore or larger? Thanks in advance for your help.

[Clem Z.]

Re: L72 Piston Number Question

these are L-72 piston made by TRW for GM. they are the 11:1 pistons and i think they used the same forging # for all bore sizes

[Joe L.]

Re: L72 Piston Number Question

clem-----

I think so, too. With forged pistons, I believe generally one forging was used for all pistons sizes for a particular application. With cast pistons, generally different castings were used for each size (except +.001")