Modifying a Bagheera cylinder head

[andyowl]

With a supercharger fitted we want to improve the flow of exhaust gas out of the combustion chamber. Lower pressures in the cylinder during the exhaust stroke mean less work to expel the gas and more power at the wheels. That's the theory.

Fitting larger exhaust valves is the main objective by replacing the usual valve guides with larger ones with off centre valve stem holes.

Enlarging the exhaust ports to match the larger valves is part 2. But how much metal can we remove without breaking through into adjoining passages for oil or water?

Cutting through the ports on the old cracked head seems to be a good idea. This is what we found...

Andy