gbauer, LOL you are adding more proof!
Jay,
Well its possible the weather suddenly went from bad air to great air but not likely - 6% is like going from a hot summer day to a clear dry winter day.
Another possibility is that BOTH 283/220 cars were tuned badly, the 230/155hp was an extra loose factory build (it happens if you get lucky) and all 3 had great weather. Then I could make em all match. Something like that must have happened in fact, just no way to know for sure.
What it does say is that 230/155 was really the right combo.
Too bad it didn't make it into the 63 Nova (the 292 didn't exist yet in 62 so I assume those parts didn't either).
Since the 62-63 Nova was unfairly denied its 283 and 327 factory assembly manual options by GM Corporate (they didn't want the little Nova to kick butt on the Skylark, F35/Cutlass, and LeMans), the 230/155 and the chrome would have made a nice, mild-mannered "SS" Nova option instead of the doggy-dog 194.