best way to get 450-500 hp out of a pontiac 455?

Question

I would like to do this using stock external parts ie (heads, intake)
But internally it doesnt matter. ie (cam , crank , pistons)

Answer 1

By using the stock intake manifold you are limiting the amount of fuel/air that can get in there but I would recommend a high performance Eddlebrock carb, intake and cam. Eddlebrock will match them to your needs and it will all perform solid with a relatively stock looking setup. You should also look into electronic ignition if the car originally has points & condensor. That should be good for the 400-450 range.
500hp is a lot out of a stock motor from that era. Without supercharging you will most likely get more power from a serious head. When you get into crank and pistons you are talking serious teardown. You might as well start with a fresh motor and keep your original motor as stock. You can bolt it back in later if you want to keep the originality of the car for resale purposes.

Answer 2

One horsepower per cubic inch is no big deal. Have the heads professionally ported and matched to a strong cam and intake manifold, aluminum if you can afford it. Headers obviously, with a low restriction exhaust. Keep it under 5500 rpm unless you have forged crank and rods.

Answer 3

contact a boat engine builder because those boys know pontiacs. but using stock parts and that kind of h.p. is almost impossible. highperformancepontiac.com might also help

Answer 4

bore out the heads hi performance intake, headers, hi performance cam, crank, pistons, rods, lifters,

Answer 5

Not gonna get that kind of HP from stock unless your mechanic is a genius.Turbo will not get you there unless you rebore and refit the entire engine (and still.....). Best bet for that kind of HP is change the engine and tranny.

Answer 6

unless moneys a big matter, do it all and just have a tire roasting, frame torquing monster under your hood=)

Answer 7

set her up with a turbo charger