Any modern engines or engine builds for modern results?

1970boy said
Thanks for the insight and info i really appreciate it, also where you say "good gearing" and "machining, assembly, tuning, done right" can you give more specifcs on what that would be to give me an idea on what to do for my build i want gearing to have decent get up and go in the city without sacrificing highway mpgs and as far as machining and assembly what should be done? Over bore . 30? Zero deck?

I would first find a competent machine shop (try to get recommendations for your area) and take what you have to them; they will be able to tell you all that it needs. The bores might not need to be increased that much; maybe .020" will be enough to clean it up and there are off-the-shelf pistons in .020, .030, .040, and .060" oversize but you won't know for sure until it is inspected by an expert. I would definitely recommend having it decked to blueprint, in fact square-decking is the way to go but I've heard some shops can't really do that properly so perhaps look into that (ask). Also have the rotating assembly balanced once you find out the bore-over and get the pistons. Lastly make sure the cylinders are honed with a torque plate (mimics the effects of having the heads bolted on which slightly distorts the bores from the clamping force).

Tuning would involve either getting a proper spark-plug reading tool (like a scope that an ear doctor uses) and/or a wideband O2 sensor with air/fuel ratio readout and tuning the ignition timing and A/F ratio to where you have a reasonably lean cruise mixture and plenty of vacuum advance and an advance curve that suits your overall setup (weight, gearing, trans, etc.). For gearing it's generally accepted that 3.23:1 is the best all-around ratio; tire diameter will change that too so depending on that 2.94s or 3.55s could work as well. But then if you run an overdrive transmission you could run shorter gears than that say 3.73-4.10:1...

My '70 Duster currently has 2.94 gears in the rear and I plan to put in a 2600-stall converter I have on the shelf. I will probably swap to 3.55s for better performance but I know my gas mileage will take a dive, which I'm OK with because I'm turning it into more of a weekend fun/track car than a driver which it used to be.