As the lads have right said. 3BN fits but has a restictor, combustion ring, on it which is not good.
Avoid heads with pitting as they are no good. You want a nice head that has no pitting. If its sooty it can be polished but it's actually a known fact that sooty heads can actually increase performance, at the risk of reliability.
The soot acts as an insulator in the combustion chamber. Higher temps result in faster moving aor molecules. This gives a greater thrust onto the piston. But the excess heat can lead the engine into detonation, amongst other issues.
Personally, fascinating subject.
