383 Piston slap

4032 shouldn't do that, unless they are installed too loose.
If those Diamonds are 2618, that's expected, and normal, and nothing to worry about.
A friend and i ran a 440 in a Duster with CAST pistons at .008 (supposed to be around .001-2) and the piston slap was noticeable, and didn't go away when warm.
It must have been a problem, the car would only run mid elevens at 115.