Vannin' Home Forums Chevy Performance (GM) What is your most beneficial power train upgrade?

I can on the bike

Maybe

I get 14 mpg with or without the a/c on. Going up steep mountain interstates drags it down to 45mph and no OD. Driving around town it drives normal if not in OD. I'd love to be able to drive the van with lots of generous horsepower. Other than performance issues, the engine does ok and has no oil leaks, doesn't use oil except for a valve cover gasket that needs changing.

I had several engines in the 83 mostly just messing around. In my 83 the 305 always got 18-19 highway and about 13 mpg in-town even making about 325 hp. 350 TBI with the Weiand 177 got about 18 mpg highway and 12 city. The cammed single plane intake TBI Vortec 350 making about 425 hp got about 1 mpg less than the 305 too. The 383 Vortec TPI making about 400 hp at the crank and probably every bit of 500 ft/lbs got about 21 mpg highway and 14-15 city. NONE of them really worked that hard to get up to speed. 700r4 and a 3.08 gear.

Shooting for 20 mpg highway out of my 1-ton converted 97 Express with a 475+ HP 383.