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Re: [oletrucks] Engine identification

To: Old Trucks List <oletrucks@autox.team.net>
Subject: Re: [oletrucks] Engine identification
From: J Forbes <jforb@mindspring.com>
Date: Fri, 19 Dec 2003 21:49:53 -0700
> Date: Fri, 19 Dec 2003 13:42:45 EST
> From: Spinningroach@aol.com
> Subject: [oletrucks] Engine identification
> 
> Hi guys (and gals)
> 
> Does anyone know what the numbers 10 and 11 that appear on a '68 327 engine 
> pistons mean ? Is it possible to tell from these numbers that the engine has 
> been rebored, and if so to what extend or on the opposite that it's fully 
> original? (The upper rings have a 0 on them - nothing on the others)
> 
> Thanks in advance for any input! JP

Sometimes pistons were marked for size (tolerance) before engine 
assembly at the factory.  But if the engine has been rebored, and 
oversized pistons are installed, you should see a number like "030" 
stamped into the tops of all the pistons.

Also, original cast pistons will have "GM" cast inside the piston, but 
replacement pistons made by other companies will not.

You will want to have a machine shop look at the block, and see if it 
needs boring again (which is very likely), they can measure the bore 
accurately and tell you what size it is.  Although I can usually measure 
with a steel ruler close enough to tell if it's standard or .030 or 
.060" oversize.

-- 
Jim

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