My h/c Z made 560'ish, trapped 134mph consistently, and would beat the daylights out of my buddies 3.4 whipple cobra that made 750whp. He would run even with me till the top of my 3rd gear/125'ish, then drop anchor. I love both cars but you are going to need 750'ish to run with him from a 40-140 roll.
A 750rwhp Cobra that is running properly with a good driver is a 145mph+ trap car, your buddy should of walked you until aerodynamics kicked in but you would be far behind at that point.