Fix (alu weld) and file back to original any serious surface\edge damage, with large parts (warp\uneven) 'work them' using valve grinding paste on glass surface. Good 'thick enough' gaskets. A drop of blue loctite for carb things, bolts etc (if\when needed).
Avoid any further\new damage by careful and slow cross-tightening of bolts\nuts, especially important if the gaskets are thick.
Never over-tightening. The (perfect ...well, good enough) surface\gasket should do the job, not the extreme force on the bolts\nuts.
And zero stuff that could creep around to the oilways.
Just my opinions.