If you are going to talk about flat face lifters, you need to get some terminology straightened out. It really makes a difference.
Radius means SPHERICAL or as in curved or as in a ball bearing type surface.
Tapered means cone shaped as the face of most modern so called flat lifters.
Flat means no curve or taper.
Radius lifters were tried many years ago and did not work for very long because of the high unit pressure. A spherical surface results in single point contact with the cam. A taper was the obvious better choice.
Ford started out making lifters flat faced. Somewhere during the model A production era they changed to tapered. Somewhere during the 49 to 53 V8 production they tried orbital grinders for a full radius but went back to taper after a short trial.
The taper on a flathead Ford lifter is .0003.
And yes, there are quite a few shops around the country that still do lifters properly.
Cam Guru Help, Correct lifter to lobe offset & lobe widt
Moderator: Team
Re: Cam Guru Help, Correct lifter to lobe offset & lobe widt
Not as much as a PITA as having to strip the engine because the cam ate the Chinese lifters...