I have a BDR #461 with a Roush 402R and a TKO 600 5 speed. This is a great balance engine for the money if you go the Roush route. The advertised HP was 515 and 500 tq. The engine dynoed at 484 hp. The engine has a mean idle, revs quickly, and pulls the car hard. You still have to start with a rolling start and then ease into the throttle or you will just break loose the tires. You can go big and go for the 427R, but unless you absolutely have to have a "427", I don't think you wil find much difference for the money. Put it towards the tranny or another item.
I don't have any time slips for comparison, but when you own one of these cars with almost any engine combo, the only car you should be afraid of is another cobra or one with blue lights.
Check out my photosite for the engine installed.
www.jlennon3.photosite.com