WTB 2Ltr Engine, can be a bare Engine

Hi all,
looking for a engine for my sons 75 Kamper, has developed a great knocking noise and do not want to spend $6k on rebuild.
So after a 2ltr Eng that i can throw in to get him going again, does not have to be complete eng that has everything bolted to it can be just a bare block (main case and heads, rocker covers) that i can use all my eng bolt on parts.

Cheers
Bill