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Patch

05-11-2021 01:49 PM

1972 BB 402 question

1 Attachment(s)

Hey there. Opened up a new to me 402 last night. No ridge at all in the cylinder walls. The pistons are what appeared to be factory pistons, but what's with the hole in each one? Some had a 9 stamp, some had a 10 stamp.

b454rat

05-11-2021 04:03 PM

Re: 1972 BB 402 question

Hole faces towards front of engine? Kinda big for a marker if so

The Rocknrod

05-12-2021 01:14 PM

Re: 1972 BB 402 question

I've seen locator pins in marine performance pistons but that hole doesn't "look" like one, just a drilled hole.

GASoline71

05-12-2021 02:06 PM

Re: 1972 BB 402 question

That is a bit big for a mark to orient the piston towards the front of the engine. Those don't look stock to me. What heads are on it? Stock? If memory serves me right, old school engine builders would do this to reduce the compression ratio just a bit.

Gary

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