'69 L-71 piston design question

[G A.]

I want to make sure I have the original design wrist-pin and I can't recall for sure what they were. Were the factory pistons a center pin or off-set pin, and were they pressed fit or floating pins? Hopefully someone here has a better memory than me.
- Dan

[Clem Z.]

Re: '69 L-71 piston design question

for sure pressed pins and if it is a cast piston most likely a offset pin.

[Michael H.]

Re: '69 L-71 piston design question

I want to make sure I have the original design wrist-pin and I can't recall for sure what they were. Were the factory pistons a center pin or off-set pin, and were they pressed fit or floating pins? Hopefully someone here has a better memory than me.
- Dan

If I remember correctly, the 390/400 HP pistons had offset pins but the L71/435 HP pins were on center.

[G A.]

Re: '69 L-71 piston design question

Thanks gentlemen. My recollection was a center pin but I couldn't say if they were floating or not. The dimple rods certainly had pressed pins though. Would anyone know what current manufacturer has good duplicates (pressed, center pin, 11:1 comp)??

[Joe L.]

Re: '69 L-71 piston design question

Thanks gentlemen. My recollection was a center pin but I couldn't say if they were floating or not. The dimple rods certainly had pressed pins though. Would anyone know what current manufacturer has good duplicates (pressed, center pin, 11:1 comp)??

Dan------


The original pistons were forged aluminum, center pin, and press fit. Until the LS-7 came along a few years ago, the only Chevrolet engines that ever used floating piston pin design were 1969 Z-28, 1969 L-88 and ZL-1.

If you want to stay with a forged piston, Speed-Pro/TRW is probably the best way to go for a street engine.

[Richard F.]

Re: '69 L-71 piston design question

68 L88 used floating pins with 3/8 rod bolts as Joe has pointed out before.

[Duke W.]

Re: '69 L-71 piston design question

The '69 AMA specs that you can download from the GM Heritage Web site should have that information.

The '63 AMA specs state that the 250/300 HP engine pistons had .060" offset and the 340/360 HP engine pistons had none.

Duke

[G A.]

Re: '69 L-71 piston design question

Thank you all for the feed back. Now on to the search for the pistons.
Dan