Unless you check it with a degree wheel its just a guess. I'd use the 2 or 4 degree advanced keyway if just guessing. But I'd try to buy or borrow the tools to degree it. When it doesn't run that impressive the first thing everyone will tell you to do is degree the cam.

Sell the PRW rockers, use the money to buy correct length pushrods if needed and/or valve springs (definitely needed), and use the stock rockers.

With an RPM intake and 1.75 inch headers I'd guess that it would make about 350 horsepower tuned up nice. In an A body with sticky tires, 4.10s, and 3000 stall it would be a good runner.