For the most part 1 hp. unless you rev up to max rpms. You can rev up a lot faster with a udp. Most udp are rated 7-8 hp. I have herd people say a 2 mile per gallon gain, but I do not know how accurate the report is.
new engine,1.7 rocker arms,Pipes exhaust, shorty cats , shorty headers,under drive and overdrive pulleys,4.2 upper plenum, throttle body spacer, cold air intake, stage one clutch, shorty shifter, and tune. 8.8 in storage