I have a 72 455 that was rebuilt in 92. The pistons have only these numbers on the bottom: 285-99, underneith that is an upper case T, in a upsidedown triange?
Any info would be appreciated,

Dale

 

Post a pic of the dish.

 

It's a running motor, but on an engine stand, about to go in my car. Haven't seen the top, only the bottom, via the removed oil pan.
Wasn't going to pull the heads if I didn't have to.

Dale

 

LuxBlue on the H.A.M.B. was wondering this same thing.

Unfortunately, I'm of no help.

 

Sure sounds like a Speed-Pro/Trw early forging to me.
My set has the same markings.
That is NOT the part number, nor do I know what the meaning of that is, I just know that my set of Forged pistons have the same markings on the underside.
Mine is a set of early (pre-coated) L2323F .030 units.
Jim

 

During my research this morning I came across a Monte carlo SS blog, where a guy with a small block chevy had the same numbers on the underneith side of those pistons. He assumed that the numbers were the jullian date of manufacture. I would say deffinately not?

So Warhead, yours are a set of L2323F .030, and you know that because? And what is precoated?

Thanks for the input,
Dale

 

I know this because I can read.
Mine are new, never been used, nor have they even been on a rod, still in the box.
You posted exactly what was on the under side, I concurred with what I have, I posted exactly what is on the top side.
The L2323F .030 (top side marking), IS what is stamped into the top of each one.
The bottom side markings, is now, all up to you to figure out.
I am confident you have either a set of L2323's, or a set of L2390's.
Jim

 

Jim, I have no doubt that you can read, you seem well spoken.
Upon researching the part number that you provided, theses pistons come in either:
Stock
.030
.040
.060
I suppose if I opt out of pulling the heads to take a visual, I could take a cylinder measurement from the lower end to determine bore size?
Thank you Jim, you've been a great help in identifying these pistons.
Any additional input is welcome.
and what is pre-coated?

Dale

 

Nowadays, they have a black coating on the skirts for superior wear characteristics, or something. Not sure, never used a set of the newer styles.
My sets all have been the older, non-coated (hence pre-coated) Aluminum skirted versions.
Take a look through the plug hole, and see if you can get the part number from the top of the piston.
You may have to crank it some, and use a pen light.
You can get a measurement from underneath, that will not clue you in on what dish size you have. About 5 years ago, you could still get the L2390F piston, which had a deeper dish than the 2323-14.5 cc dish. That piston would give you around 8:1, the 2323 will give you about 9.5:1 compression.
Hope this helps.
Jim

 

OK Jim, a pin light makes sense. I'll take a look this weekend.

Dale