None of the STC’s list any specific performance numbers other then stating that it exceeds the original performance.
I have owned a 1976 AA-1B for over 40 years and in 1983 I installed a 0-320. With 150HP, a 58″ pitch Sensenich prop and no fairings (this was a stock Trainer), I see cruise up to 135MPH, but normally cruise at 120 – 125 to save fuel. I don’t have any aux fuel.
Takeoff and climb are great. At my home near sea-level airport the first turn-off is at about 1,000′, and I am normally off the ground in 600-700′ at gross on all except hot days.
ROC is in the 1,000fpm range, and I have flown up to 14,000′ still climbing at a couple hundred FPM.
I am building up a ’69 American Yankee that will have a HC 0-320, it will get all the speed fairings, and a 62″ pitch on the prop and I hopefully will be installing aux tanks (have the tanks, but need paperwork). I hope to see cruise speeds well over 150MPH with this plane when complete.
There are lots of variables with the 0-320 installation, there are 3 major STCs that most were done under and there are differences between them. Feel free to ping me if you need more information.