You could build a clone of my 383. It dynoed at 450 hp and 467 ft. lbs. of torque. And it is very street friendly. Here are the specs:

AFR 195 heads (I used their 190's but they don't make those anymore)
SRP forged pistons (10.6:1 static compression; 8.42 dynamic compression)
Eagle I beam rods and cast steel crank
CompCams 280 Magnum single pattern flat tappet cam (.480 lift; 230 degree duration @ .050)
CompCams Magnum roller rockers
Edelbrock RPM intake manifold
Edelbrock 750 carb
Beefed up 700R4 transmission with a 2500 stall converter.

If you have the money, you could upgrade by using CompCams hydraulic roller version of the 280 Magnum cam. If you do, I would add AFR's rev kit.