Not a reply, but an update. I found the casting numbers, but since it's a Canadian truck, the number isn't on the usual lists. The engine SN does not match the truck ID plate, so I know a swap has been done somewhere. Block casting is 3830327, SNC359288 (came with X289759).
As for the 60, the casting is 3850817 (62-78 230-250), SN 125162453E. I still can't figure what size it is. Was told 235, but the dist is on the front, not in the middle. Hope this helps with IDing these engines.

Aint it grand getting the trucks with their second (or third) engine?

Current fleet (subject to change w/o notice)
\'49 GMC 3/4-Ton , 60 Austin Healey Frog-eye Sprite (some assembly required), 2011 Dodge Avenger, 2015 Jeep Cherokee. No, they don't all run.
My other ride is a (B737)no, (B767)no, A320.... Update... was Embraer E190, now Boeing B787.

Knowledge is a wonderful thing, but ignorance means you don't know you can't do something.