What piston is this L2350 ?

Just acquired a 1970 383 HP engine, pulled the 906 heads and found .030 over pistons with L2350 stamped in them. I checked google with no help. Anyone know what compression these pistons are claimed to be?

Is that an old KB piston # ? Sounds familiar.
I looked on their site, and their part #s have changed, so the current 4.280-bore 383 part is UEM-KB210-030.

Nope. 50+ year old Trw/Speedpro forged Pistons.

Compression will likely be pretty low.

I might have an old Speedpro catalog in the shop. I will look tomorrow.

Edit: now that I think about it, might be a Trw/Speedpro cast stock replacement piston. Flat top, no valve notch, terrible compression ht. Might get 8:1 probably less.

Aha - forgot about those old heavyweight TRW slugs - thanks.

Anyone know the compression height for the 383 magnum engine?

1.93 compression height
9.98 deck height
6.387 rod
3.387 stroke -1/2 is 1.69
9.98 - 6.387 - 1.69 = 1.89 so .042 above deck

anyway number could have been mis-read? there is a 2315 383

If they don't appear to be zero deck , the 2315 is about .020 in the hole , tallest replacement available , your compression is near 8.0 with a 906 not cut much..

I think you meant BELOW ???? ... that's even above the bloated NHRA spec of .021 above the deck , there wasn't a 383 built for production passenger cars or trucks with a positive deck height piston .

Some of your specs are incorrect , stroke for the 383 is 3.375 , 400 is 3.38

68-69 383 HP and 2bbl with a dish pistons are 1.932 , on a blueprint deck these pistons sit .0025 in the hole , that's the tallest B 383 CH piston.

What year ?

68-69 are 1.932 I do not know if 70 is the same ?

Not mis-read, definitely L2350.

Stock stroke is actually 3.375”, and the correct rod length is 6.358”

"What piston is this" kinda sounds like the beginning to a drag racer's Christmas song.

383 and 400 are the same, but I wrote some numbers down wrong, do the math. 1.925 plus rod length plus half the stroke (1.6875) then compare to deck height of 9.98. Still 9.9825 I went online to get those specs, I’ll re check them

Brain fade, looking at the numbers AND still wrote down wrong! lol

or... if you shave them about .050 and put them in a 426W block with a 4.15 crank and 6.76" rods you can make a low buck 478" RB

I found where Trw said that all L2000 series are forged and if it ends with an F it has floating pins.

Someone on FABO ID'd these as - 70-71 383 2 barrel (non HP) 1.863 compression height.
I have not yet been able to confirm this.

The L2315F Pistons that they still sell have 1.92 compression height.

My piston spec was wrong , corrected.

I'm pretty sure the 400 crank has that .005 longer stroke, it's a cast crank so it's not the same crank as the 383 .

That is the tallest available aftermarket 383 piston , sold I believe as an NHRA replacement , it's as heavy as a stock cast piston except it's forged.