The cylinder head was removed from the engine, disassembled, and cleaned. The head was pressure checked by the machine shop and passed for rebuild. I proceeded to give the head a port and polish. The amature port and polish was similar to a stage one modification described in Peter Burgess's book How to Power Tune MGB 4 Cylinder Engines and Sean Brown's Flowspeed website. The head went back to the machine shop for valve guides and hardened seats. Final assembly was performed by me saving a few dollars. New valves, springs and guide seals were installed an the head. A new nitrided rocker shaft replaced the worn shaft. The rockers did not need to be rebushed.

Cylinder head re-build, parts, and machine shop.

Parts
Rocker Shaft, nitrided
Valves Intake, stock
Valves Exhaust, stellite
Valve Guides, magnesium-bronze
Valve Guide Seals, Moss heavy duty seals 290-890
Valve Seats Intake, stock
Valve Seats Exhaust, hardened
Valve Springs Set, stock

Machine Shop
Cylinder head checked for cracks, valve guides installed, valve seats installed

cylinder head cylinder head cylinder head
cylinder head cylinder head cylinder head
cylinder head cylinder head