For my deal I put a tilton super starter on and prob solved works great.

Problem Solved.

Water was leaking into the exhaust manifold from the riser gasket causing water to get into cylinder 5 causing it to hydro lock. This would cause the starter to jam, grind and break.
Fixed the gasket and now it turns over every time. Fortunately I did not damage any internal parts.

Buddy of mine told me had this happen on a motor he had.