I just aquired a new truck it's an 84 chevy K10 with a 350 and a 4bbl auto with OD. Does anybody know the horsepower numbers for a stock motor? It has headers, dual exaust, and a filter, is there any other wasy to improve the gas mileage, i was thinking mabye a performer intake, or will that just make it worse? Thanks.  

Hey Ben! The stock hp in a 1984 350 motor should be 165. I've seen in muscle car mags people swap old Q-Jet manifolds (I believe that's the name for old GM's stock cast-iron manifolds) for Edelbrock's Performer. What I saw was that below 3,800 RPM the stock manifold made the most torque. (327 *** I also saw that the RPM air-gap manifold kicked the performer's butt and was almost as good as a Q-Jet from 1,500 to somewhere around 3,000 rpm. If you need as much torque as you can get at or below 2,800 rpm stick with the stocker. If you want great peak torque somewhere above 3,000 go with the air-gap. If an air-gap won't fit and you don't want to sacrifice torque below 3,200 to 3,500 rpm you probably don't want a performance manifold. You might wanna try "port-matching" the exhaust ports of the manifold to the manifold gaskets and de-burring and smoothing irregularities in the manifold instead. If you want more power and better mileage try a higher energy aftermarket ignition like Jacob's offroad ignition. If your local authorities will allow it, buy high compression heads like GM's "fast-burn" heads. Since aluminum disipates heat better it allows higher compression ratios on the same octane rated gas.

If it were my truck, I'd buy new heads and an ignition system.

Good luck!