A friend of mine built a 383 w KB pistons and didnt tell the machinist. The engine sounded like a diesel. I just measured the clearance roughly with a feeler gauge and a .08 fit. Actual clearance was prob a touch bigger.

Take care,
Rick
68 Coronet R/T 440 & 68 Charger 528 Hemi,and 5 Challengers! 6 cyl, 318, 360, 383, 451