[FFR428]

Guys, the std 428 is a IU. The 428 CJ a IUB or "A" and the 428 SCJ is a IUA or "B". The A & B crank are the later version and should have the IUB or IUA on the #7 counterweight also. Different piston weights were the reason behind all the CJ/SCJ cranks. I have a 428 CJ "A" crank with IUB and "69" cast in. The 2U, 3U etc...are 390 cranks. No matter which one it is they all have a casting number or markings of some kind to ID it. G.