Headers vs 340 manifolds

I have a few sixties speed equipment catalogs. There were full race cams, 3/4 race cams, 3/4 full cams. Had nothing to do with 3/4 mile tracks; 3/4 was hotter than stock, milder than full race. The terms date back to the flathead Ford V8 days. Instead of trying to copy a page out of one of my old catalogs, I'll offer something I lifted off another forum, written by Jack Vines, who specialized in building hot Packard V8s and who knows Ed Iskendarian (Isky cams) personally:

From Ed Isky's lips to my ear: "The 3/4-grind came from Ed Winfield. Lots of guys had to be able to drive their race cars to the track and wanted a street/strip cam for the flathead Ford V8. His 3/4-cam was streetable, would idle. A full-race grind wouldn't maintain an acceptable idle on the 255-276" engines. When I got going, our flathead 3/4-cams were usually around 250-260 degrees advertised duration and around .325-365" lift. The full-race grinds were 262-270 degrees and .404" lift.

When OHVs came along, the E4 was a street/strip 3/4 grind of 260 degrees and .425" lift on a cast iron billet core. The E2 was a track 3/4 grind of 256 degrees and .450" lift on a welded-hard-face core. The tungsten carbide, chrome, nickel alloy was developed in germany and introduced to the US by GE. It required chilled iron lifters and was the best we had then for high spring pressures. A full race grind hard-face cam started at 270 degrees/.450" lift and eventually got up to 320 degrees/.510" on the 505-C Magnum. These were a very low-intensity grind, as the springs and pushrods back then wouldn't handle the acceleration rates we see today.
thnx, jack vines


Jack Vines
Studebaker-Packard V8 Limited
Obsolete Engineering