Originally Posted by billonwheels
I was wondering what my Horse Power would be on my 1971 HO 455 Pontiac. I've heard it would be less than the factory, (330). I can't belive that. I have a 278 duration cam and lifters from Edelbrock, Edelbrock Perfomer manifold (spread Bore), it's bored 30 over with a Edelbrock 1411 750 Electric Carb. Roller rocker arms, Edelbrock 110 fuel pump, with a HEI dizzy. TH 400 Trans rebuilt with a B&M 2500 stall and B&M shift kit. The engine had 70000 original miles on it. My guy that did the machine work says at least 425 HP, 495 torque. Another guy that build engins says I went backward in horsepower, SMH.....everything I've read says 425 is a realistic number. I even got the billet pullies and an electric fan....
It depends on how much work (if any) was done to the D-ports on the engine now. If it had the original heads it might be making more power than the estimated 425 hp and 495 ft/lb.
It should be a strong running combo, though. Easy 12's. If you take it to the track or if you've already been, the mph and weight will give you a good estimate of the hp.
I would be a little concerned the TC stall might be higher than 2500 if that estimate was based on a 350 SBC like many converters are. Hopefully the actual stall speed is at or below the torque peak.