Turquoise maxi does mid 50’s on a stock modded magnum pipe. Magnum did mod 60’s first time I built it but I sold it and bought it back and re-did it with powerdynamo and not a curved ignition as it had before. Still think it touches 60 but I don’t really gps them cuz I know there at least the fastest around, and I honestly don’t care. Just keep em running well. Both are reliable.