# Keep these pistons or toss them?



## jhogan2424 (Mar 28, 2011)

Just got my first GTO! It's a 66 in decent shape but it's gonna need some engine/tranny work. I was looking for some info on some pistons that came with the car and ran across this forum and thought someone might be able to help me identify them. They have TRW L2280 stamped on top of them. I'm not sure if they are worth keeping or even which engine they are intended for. Anyone have a clue?


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## pontiac (Mar 6, 2011)

Pontiac 400 forged pistons, but mic the pistons so you know if they are stock or oversize. The oversize will fit other bores, like 428. not worth keeping, send them to me.


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## BearGFR (Aug 25, 2008)

jhogan2424 said:


> Just got my first GTO! It's a 66 in decent shape but it's gonna need some engine/tranny work. I was looking for some info on some pistons that came with the car and ran across this forum and thought someone might be able to help me identify them. They have TRW L2280 stamped on top of them. I'm not sure if they are worth keeping or even which engine they are intended for. Anyone have a clue?


Speed Pro / Federal Mogul has taken over the TRW piston line. I did find one (but only one) reference that suggested what you have might be +.060 428 pistons, but it wasn't a reliable source so don't take that to the bank just yet.

Bear


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## jhogan2424 (Mar 28, 2011)

Thanks for the info! They also have a 030 stamped on them so if I understand right they are .030 overbore 400 pistons for stock stroke/rod combo? Any idea of Compression Ratio?


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## Mr. P-Body (Jan 20, 2011)

I don't recall seeing that part number before... HHMMM...

Pontiacs usually have flat-top pistons and control compression with chamber volume. Your heads are what determine the static compression. What are the casting numbers?

Jim


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