I would venture to say more like 540hp and 580tq, or more! Your runnin a meaner set up then me, and im at 505hp/580tq. Im runnun a 502 crate from YearOne with alumn Eldebrock heads, intake, and just a Holly 870. Its strictly a driver, so 9.8 compression, 92 octane, Blvd cruiser n back road bruiser Man i cant wait till spring to get her out again!!! You are gonna Love cruisin your ride, bro. There is nothing cooler then a big ol' Impala snapin your neck back when you get on the loud pedal!! Best of luck, bro
Im a diehard Classic GM guy. Nothing beats the beauty, power, and style of great american engineering!! '67 Impala w/ 502 BBC, 505h.p.
You can load up CompCams free cam picker software as it is a disabled copy of Desktop Dyno Software from 2000 (CompCams bought the company that wrote the software along with a few other companies so they give it away now).
Plug in all of your information including flow numbers from head manufacturer's web site as it is a pump and fill simulator program that aproximates horsepower a little optomistically if you don't give it good head data. Even then it is generally 25 to 30 horse high but other wise pretty good for most of my BBC builds.