As I understand it, the engine he's using is a pushrod chibrolay out of a truck. Everybody knows you can buy a junkyard chibby and install a $39.95 cam from the internet and get at least 500 horsepower from it. Just check some of the dragrace forums. They do it all the time.
What I like about SKM's rear upper arm design... is that it's 3-way adjustable. I wanted something like that,,, for dialing out the negative camber at the ball joint that causes the rear tire wear. But you would also need the 2 adjustments at the cradle to keep caster in spec. I actually thought about designing some sort of cam bolt for the upper arm mounts at the cradle... but that fell off the priority list a loooong time ago.
By "prototype"... do you mean you're doing the mock up on the arms,,, then sending them out to be built by an aftermarket manufacturer???