I think it is around 3 thou, but i will try and find my spec sheet. The clearance is smal er than some think, and not the 6 or 7 thou which used to make the big "rattlers" when cold. I assume TRW forged is the same piston as well, just named different. There is a website somewhere if you search. I found one a few years ago.
I know 45 thou is a lot, if its n/a probaly 25-30thou would be my GUESS, i'm sure I'll be corrected tho.
THE CLEARANCE YOU ARE SUGGESTING IS MAYBE PISTON TO HEAD CLEARANCE PISTON TO BORE IS ANY WHERE FROM .002" TO .009" DEPENDING ON SKIRT STYLE .MOST PISTONS HAVE THE CLEARANCE BUILT INTO THE PISTON IE= 030 OVER PISTON WOULD MEASURE SAY .023 THEREFORE IT WOULD HAVE .007 " CLEARANCE