We have been sevicing NC and SC since 1960 

All heads have been pressure tested, vacum tested, and we also check to insure the injector goes in smoothly and the oring doesn't hang 

We have 18mm and 20mm available to ship

THIS IS FOR A SET OF ORING CYLINDER HEADS

Just specify what you need when placing the order in the notes. 

HD springs are available as well for 220.00

6.4 push rods for 100.00

If you have any questions let me know