[Alan70]

I’m thinking they are Mahle but I can’t find the part number anywhere on the internet. In the picture it has what looks like a capital M with 1105 above it and 0290 below it

 

[bracketchev70]

Hard to tell. Looks like an early factory piston.

 

[chevydealer35]

I think Bracketchev 70 nailed it---i doubt that it's an "M"---looks like low compression factory units to me as well.

 

[Bobsoldcar64]

They look like TRW. I had a set of those in a 355 I built years ago

 

[Bobsoldcar64]

The TRW flat Top pistons with 4 valve reliefs. Forged. Look them up. And take a peek. hope this helps you.

 

[Alf]

 

[Alan70]

Yes Alf, as in my picture the same ''M''. where did yo find this info?

 

[Alan70]

Close up

 

[Alf]

Alan, here you go.....pg 8

https://www.mahle-aftermarket.com/media/local-media-north-america/pdfs-&-thumbnails/catalogs-and-literature/pistons-and-rings/pi-20-09.pdf