I've heard of a few different ways of getting performance out of the Slant Six. I've got a 1971 Valiant Scamp, A/C car with 29,000 original miles on it and I want to improve the horsepower, while still keeping it streetable. Can some tell me what horsepower gains I can expect by putting on the Super Six Setpup, Dutra manifolds, Cam, and having the heads redone? And can someone tell me the price for the parts and how to go about putting 3:23 gears in the back.

Thanks

Start with a good tune-up and a valve adjustment.
Advance the initial timing until the engine pings, then back-off 2 degrees.

A free flowing exhaust system will also help and the lower rearend gear ratio will give the car more off the line "spunk" but at the expense of higher freeway speed.
DD