Top End Refresh: Part One | Branch-O'Keefe Head Porting/Polishing

09. John keeps an assembly line of mills to save time from changing bits and switching up measurements. Here John cut 0.030-inch from the deck surface, when all is said and done a total of 0.050-inch will be cut from the surface.

10. This mill was used to re-cut the combustion chamber to fit the larger valve seats.

11. Here are the larger Martin Wells valve seats ready to be installed (the larger at right is for intake, the smaller is for exhaust).

12. To stuff these puppies in, John heated the heads with a torch and put the valve seats in the freezer so that when they're mated, the expanded metal from the heads mates perfectly with the cooler metal of the valve seats.

13. John delicately smashed the valve seats in with a sledge. Actually, just a few taps, and because of the difference in metal temperatures, the valve seats mated to the ports fairly easily (sometimes they fall right into place, according to John).

14. Then the heads were ported, which is the most important process. Basically, the ports were treated with a pneumatic rotary file that removed material to flow more air via the intake port into the combustion chamber and out the exhaust port. John employs skilled craftsmen that do nothing but port heads all day long. The ports were then polished to flow the increased air velocity more smoothly. The combustion chamber will be polished later.

15. John installed the Kibblewhite valve guides into the heads. The Kibblewhite valves provide great lubrication and last a long time due to the bronze manganese material.

16. Here John used a specific cutting tool to cut three angles in the valve seats: 60 degrees, 45 degrees, and 30 degrees, that all correspond to multiple valve opening clearances. This is another key components to the Branch-O'Keefe design.

17. To protect the valve seat from being damaged, John placed a dummy valve into the valve guides and the combustion chamber was polished to a high sheen.

18. It was then time to lap the valves with lapping compound. This is basically the finishing touch to finally mate the valve to its respective seat. Lapping compound is tiny bits of carbide mixed with grease and it's available in many different grits. John used a 180-grit lapping compound to finally seat the valves before moving on to final assembly.

19. Once lapping was done, the new valve stems were lubed up and installed into the heads with Viton oil seals (arrow).

20. The springs and top and bottom collars were then installed, all held in place with keepers.