Ironhead 900 3 1/4" cylinders, what are these?

Got this set off ebay a year or two ago... Unfortunately they had been carelessly packed, resulting in a couple of broken fins & a chunk out of one skirt. However they were cheap, so I just put them away & forgot about them, until now...

Does anyone know what they might be? There are no cast markings at all, one has "-60" stamped on the cam side, & the other one "5-", they're around 5.39 tall & no fire ring. As you can see heavily gauged for tappet guides & nuts... Any ideas?

Sorry about the crappy pics, could get some better ones tomorrow...