Replacement 68 340 four speed cams
Ancient thread but here goes...
Camshaft Machine Corp in Michigan is one of the largest suppliers of cam cores in the world and they supply cores to virtually every aftermarket grinder in America (plus every OEM). Look for the CMC cast into your core.
Regrinding takes material off more material off of the heel of the lobe than the top of the lobe to gain lift.
David Vizard uses his "128" cam program to choose a cam. He is on youtube.
A lopey idle by itself is a poor way to choose a cam.