You can rebuild it but would be tuff getting lots of hp.
You’d need heads, cam, intake etc.
Cost prohibitive.
Better to start with this motor. Easy to make close to 400 ponies with a cam change.
It has all the good stuff already. Good compression ratio, matched cam, good heads.
And priced well.
https://www.jegs.com/i/JEGS/059/0282/10002/-1