Is this a stock 340 piston?

[Cudakiller70]

No markings I could see, also rotated past TDC it didn't quite make it to the top of block.
If so any guess what compression?  Heads are 3671587 if that's needed for compression guess

[1 Wild R/T]

72-73 340 not 68-71  First photo 72-73 piston... Second photo 68-71 piston...

[Cudakiller70]

Thanks 1 Wild R/T

Mine looks more like the the first photo, judging by the flat width in the middle.
Are most or all oversized Pistons stamped with size on top?
My block cast # 2780930 340-5, I think is a 1971 build.

[1 Wild R/T]

Most O/S pistons do have the O/S stamped in the top... The 68-71 piston will protrude above the deck, it has a chamfer around the edge so the piston doesn't contact any overhanging head gasket..  Back in the 90's Mancini was selling full sets of 72-73 340 std bore pistons for $50.00.... I bought a set with plans to use them in a 360...  But better options started coming available before I built it....

[blown motor]

What's the purpose of the notch on the side?

[1 Wild R/T]

What's the purpose of the notch on the side?

Identifies the front of the piston... The pin is offset to reduce thrust loading...

[73_Cuda_4_Me]

The 72-73 pistons have a shorter 'compression height', and top of pistons only come up to about .085" below deck... the earlier ones are .010-.015 above the deck at TDC...

[blown motor]

Thanks guys. I'm still learning.

[Cudakiller70]

Ok, I think first picture is right for what I have stock 72-73 engine. My motor is not original , if I'm reading the stamped code on engine block in front on drivers side: HM 340 R 36440  134. Even though block casting is 1-14-71.
H= 1972

The 72-73 pistons have a shorter 'compression height', and top of pistons only come up to about .085" below deck... the earlier ones are .010-.015 above the deck at TDC...

Checked with feeler gauge and straight edge cause that's all I got right now, but came up with .077 but that's not very scientificial. So it probably is .085.