I am taking a long shot that someone might have some good info on this question. I have a set of old Arias forged pistons that are probably 15-20 years old, that I am planning on putting in a block for street use. I have had them over a dozen years.
My machinist and I are debating the clearance to run... my only experience was with the old TRW and Hepolite's and I would run them at .0035 to .004" with no issues rallying. He is thinking more like .006", which I don't like for just running around on the street.
These have no real markings.... the are flat tops, 2 eyebrows, and a raised .052" high flat dome. Under the crown they say 'Arias' and 'Alcoa' and '40' in cast letters. The material coloration is bright aluminum, rather than any sort of grey like the old TRW's were, so IDK the actual material. There are no steel strips in the skirts to control expansion. So any ideas on the piston-to-bore clearance would be appreciated.