Raw castings come from the Edelbrock foundry in California.
Most machining is done at a commercial machining center in mid-Michigan under contract (they have about 50 Makino A81 and A88 machines on site)
We install seats, guides, heli-coils, do the valve job and hand blend at my place.
Most have stainless 2.200 and 1.680 valves from REV
In most cases the springs are from PAC, the retainers and locators are from Comp.