SCS is correct on the date code and such. Now that block and crank are worth a pretty penny. Measure the cyl bore and access damage. Worst case the damage bores get sleeved. No biggie. Look for a sandscratch "C" on the back of the block. This will ID it as a CJ/SCJ. The IUA SCJ crank is unique to other 428 cranks. It used the LeMans rods from the 427 with shorter capscrews in the 428SCJ. The IUA cranks balance was helped up front with the "cookie cutter" crank spacer. It has a counter weight on it for balance. The IUA is also missing the balance weight found on the 7th counterweight of all other IU and IUD 428 cranks. If you put both side by side the difference is quite clear. Take both to a good shop and have them checked and magged. This will be well worth your while. A SCJ block and crank is well sought after by the R code Mustang guys for restorations. You can see if the back of the block has a partial vin code. It's on the little rectangle area on the left (DR) side of the block. Right below where the head bolts on. Keep in mind some vins were stamped on the head instead of the block also. So if it's not there don't sweat it. If they check out ok I'd sell them. SCJ items are at a all time high. SCJ dampers are selling for over $300! If you do find a vin on the block the owner of the car might be interested to purchase it if he's in the registry. www.428cobrajet.org is a really good ID site. Also some of the guys on the forum are pretty sharp. They know their CJ/SCJ stuff very well. Ask the seller if he know what the SCJ came out of. It might help. Reason I say sell you can go buy a really nice CJ crank and rods and most everything needed and then some to build your engine. And cash in on some profit hopefully also. If the crank has been on it's side all these years have it check for straightness also. Store it standing up with the flange on the floor. If the crank has been in the block all these years it will be fine otherwise a turn and polish hopefully. Sorry to ramble on so.......

G.