# 68 piston top markings



## Shadetree Racing (Apr 15, 2015)

i was wondering what these marks mean on the piston tops in a 68 400, i have removed the passenger head and 3 pistons have "1E" stamped on them and 1 has a "2D" stamped on it. i see no other markings on the head.

thx


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## el_papelitos (Jan 25, 2013)

Perhaps +0.20 ? Would mean it has been bored over.

Thats my guess.


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## geeteeohguy (Feb 2, 2008)

I don't think so. All oversized pistons I've seen are marked ".020" or ".030", etc. I think the numbers in question are assembly numbers. Sometimes, pistons were matched to the cylinders if there was a slight intolerance. A piston might have been oversized slightly. This is so with other makes, like AMC, not sure about Pontiac, though.


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## Rukee (Feb 8, 2007)

I had a broken piston when I first got the car and there is a "60" stamped on the top indicating it was 0.60" over bore.


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