Response to UTG and the comment section on Piston Knurling ‪@UncleTonysGarage‬

Back then 60s 70s knurling was kinda the norm on over the fender overhauls.
If the pistons were a bit loose, knurling was pretty std.
Folks couldn't afford "real" overhauls.
It was normal to do a valve grind between 60 to 80,000 miles, and re-ring around 110k+ miles.
With or without knurl.
The 12.5 Arias pistons in my 340 Dart are +0.60, been trimmed a few times down to 10ish now.
Those pistons were knurled on the second or 3rd trim, 30 ish yrs ago.
Still in there, driving it daily right now.
That car ran 2/10s off the Nat record in 70's .