I popped the bleeder and the calipers retracted. I let the master cylinder push rod loose and it was adjusted full retraction so I assumed that the internal bypass valve was exposed.

I then took my front 2# residual pressure valve out and since I didn't have enough line to make a new one without the valve in it. I took the spring and rubber diaphram out and re-installed the valve which is basically open now.

My brakes work but I am concerned about not running the front pressure valve. I couldn't find anything that says the corvette master cylinder has an internal valve built in.