Hey I was curious to know if anyone has done a dyno proven header swap comparison, on a stock or non stock buick small block? I know for a fact that large tube full length headers generally make quite a large improvement where torque is concerned and horsepower as well. I plugged some numbers into desktop dyno with proper head flow and sortof guesstimate of what the stock hydraulic cam would look like, with an 8:5:1 comp motor, hp went from 214 to 266! And torque 325 to 382! Thats 52 hp and 57 TQ gain, I think thats a little haywire, I've never really trusted desktop dyno too much, I use it mostly to review cam characteristics and not hp. I think there would be alot of people interested to see real TQ gain from a real world header swap!
Headers are generally worth about 25 hp gain. Some tests suggest that on street cars with mufflers the shorty headers will yield about the same as full length.
I can't give a comparison info, but my stock 350 with manifolds made 210hp and at least 270ft/lbs of torque, at the wheels on a dynojet dyno. The only variations from stock were Poston intake and a holley 670 Street avenger carb, and no AC. And the car runs 14.9 at 90-91mph like this. This is 73 motor.
