I'll also be shortening the tip of the stovebolt intake valve to lower the profile of the intake valve train, leaving just enough height above the split locks to secure the lash cap in place. The roller lifters are available in either mechanical or hydraulic versions, but the prototype engine will probably run the mechanical type. Getting the early blocks drilled for a hydraulic lifter oil gallery is going to be a bit of a challenge. Might as well use the KISS principle to chase the R&D gremlins off!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!