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05-11-2021, 01:49 PM
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#1 |
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Senior Member
 
Join Date: Jul 2002
Location: Oak Harbor, WA
Posts: 703
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1972 BB 402 question
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.
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05-11-2021, 04:03 PM
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#2 |
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Senior Member
Join Date: May 2004
Location: Binghamton, NY
Posts: 3,453
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Re: 1972 BB 402 question
Hole faces towards front of engine? Kinda big for a marker if so
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05-12-2021, 01:14 PM
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#3 |
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Moderator
  
Join Date: Aug 2011
Location: China Spring, TX
Posts: 7,280
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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.
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Master Chief, US Navy, Retired 1964 C10 Step-side Short Bed - In Progress 2009 2500HD Duramax LTZ 1948 GMC Panel 1956 Big Window Stepside 1953 5 Window Chevy Stepside 1932 Coupe New Seat Foam for Bench Seats? |
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05-12-2021, 02:06 PM
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#4 | ||||
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"I ain't nobody, dork."
Join Date: Sep 2007
Location: Whidbey Island, Washington
Posts: 8,921
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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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'cuz chicks dig scars... My 1972 GMC 1500 Super Custom (Creeping Death) "long term" build thread. The Rebuild of Creeping Death after the wreck Quote:
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