kind of a dumb question but....
Fuzzy_C
10-08-2008, 10:26 PM
hey, i've built mostly pontiac engine's in my life and never done much but re-ring and stuff with rotating assemblies, i just got a 350 4 bolt short block off a buddy of my bosses for $50, and on the top of all the pistons it has a number "30" stamped on them, what does that mean?
MagicRat
10-08-2008, 11:14 PM
It means the pistons are .030 of an inch oversize.
This means the engine was rebuilt in the past. The original cylinder bore was likely worn, so the rebuilder bored it .030 and installed new oversize pistons.
While pistons are available in many oversizes, going .030 is very common for a first rebuild. This engine can be bored again if the cylinders are too worn now. Typically going to .060 would be the next step, although other sizes are available.
BTW good deal on that block so long as its not damaged.
This means the engine was rebuilt in the past. The original cylinder bore was likely worn, so the rebuilder bored it .030 and installed new oversize pistons.
While pistons are available in many oversizes, going .030 is very common for a first rebuild. This engine can be bored again if the cylinders are too worn now. Typically going to .060 would be the next step, although other sizes are available.
BTW good deal on that block so long as its not damaged.
72chevelleOhio
10-14-2008, 04:59 AM
Hmmm, I see a 383 in someones future....:biggrin:
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