360 and 390 are the same with the exeption of the crank stroke and the 428 is the same as the 360/390 with the exeption of the bore and stroke but if you use a 360/390 balancer on a 428 crank be expexting things to fly apart the 428 is externally balanced more than the 360/390 are the flex plates and fly wheels are also different so beware of mixing these parts up

i am also looking for info on when the 428 firts came out and when was the last year a 428 CJ came out

Thanks Erin