You know I've never seen one of these plate on an aftermarket intake (Edelbrock, Holley etc.). It always seemed like a bad idea subjecting your oil to that kind of heat, would probably make it break down pretty fast.
On small-blocks (big blocks don't need them because if the bath tub intake gasket), that I don't block the exhaust cross-over, I always fabricate my own heat shield. I weld some-stand offs on the bottom of the intake to attach it. You have to be careful about pushrod clearance though.
I've only done this on daily driver type engines, becauseI normally I just block the crossover by welding it up.