"the proma is a bolt on 10 mph on a pa502 with no jet change needed."
when i did the plug chop on mine, it was borderline. i live at 2000 feet, and i went to an 80 to be safe. it likes it. ripped a lttle more w/ the stock 78, but ran much hotter. i don't four-stoke, and it has cooled down a bit. i got 8 MPH more with just the proma, an 8o jet, and a notched vario.
"...the proma is a