I read this article this morning [again] about a fairly simple build on a 1966 L79 engine....output with cast iron manifolds was 361 hp and 401 torque. They added headers and it went up to 391 hp and 422 torque.
I'm not sure if your current block can be fixed, but if it can, this seems like a simple route to look at. Lots of power, you can use most of the original pieces, just need a 327 crank and the camshaft and lifters...and normal rebuild stuff.
https://www.pressreader.com/usa/musc...81547996345412
worth a look..
-wilma