First of all :MTF_wel2:
I would recommend rebuilding your motor with the parts you need. I would think you would want to keep the PK block so you can mount the clutch housing and have everything like original. That is the easiest fix out of this one. If you start changing to newer style engines then you get into alot of machine shop modification requirements and it never ends. The crack might not bother as most of the heat is above the piston anyway.
I would recommend rebuilding your motor with the parts you need. I would think you would want to keep the PK block so you can mount the clutch housing and have everything like original. That is the easiest fix out of this one. If you start changing to newer style engines then you get into alot of machine shop modification requirements and it never ends. The crack might not bother as most of the heat is above the piston anyway.