Generally speaking, induction hardening goes down about 3mm or so dealing with the diameters we're talkin about. Nitriding even further. I've talked to Ken Heard at Oregon Cam Grinders and he says on Chrysler camshafts and crankshafts alike, they are hardened much deeper than a lot of other makes stating that the camshafts are hardened almost clear to the center of the core and crankshafts he's had experience with are hardened to the tune of around 3/8". That's pretty dang deep. I'll also add I've never in my life heard of anyone having a problem with a 440 crank in a 400 because of the hardening being ground away, so there must be something to it. The Chevy boys used to do it by the truckload putting the 3.75" stroke small block 400 cranks in the 350. Never seen a mass problem there, either and all those cranks were cast. This was long before all the stroke stuff was available over the counter.
