In the beginning I drove the car 2000 miles to stabilize the engine which, by the way, came with the full California Thermactor smog equipment. After bringing the engine right up to factory specifications. I look a run on my electric chassis dynamometer and recorded 65 horsepower at the rear wheels. Weighed against the 120 advertised horsepower, this sounds as if some guy at the factory forgot to give us a full load, But such was not the case, and I would like to digress here for a moment to explain a few pertinent facts about horsepower measurement.
Enriching Carburetor Air/Fuel Ratio
Our first run on the dyno gave us a rear wheel rating of 65 horsepower at 4000 rpm. The air-fuel ratio meter read 14:1, from past experience; this had proven to be quite lean on our particular meter, so we immediately decided the first step would be to enrich the mixture slightly for a little better horsepower reading. The standard jet was found to be 62F, so we decided to enlarge the jet size to 63.5. Our second run on the dyno brought the air-fuel ratio to 13.4:1 and netted us a reading of 71 horsepower at the rear wheels (which proved to us we were headed in the right direction).
We then took a check on the spark lead and its effect on the horsepower we were getting at the rear wheels. An initial lead of 10° offered us the best all-around ignition setting, even though factory specifications called for 5°.
Effects of Thermactor
By removing the air cleaner, we were able to come up with an additional one horsepower rating, which in this day and age is not bad. We were also curious about the Thermactor device, so we disconnected this unit and took another horsepower test. Lo and behold, we neither gained nor lost a significant amount of power. This should be a revelation to a1l of the people who have cars equipped with anti-smog devices -- they do not seriously affect the horsepower output of the car. On the other hand, I must confess that such units do not help the idle nor the low speed running. However, where they are required by law, I would certainly recommend you leave them as is, and be certain they are operating properly.