The 4.9X grind was used in more championship winning and lap record setting2.3 race engines in 2023 than any other camshaft on the market. It is the largest, highest horsepower producing cam we offer that still will get off the corner. It is made to be turned up and will not stop pulling if the head flow is there.  Expect massive top end power from RPM ranges of 4900-8900rpm+. We recommend our matched Beehive X series solid roller valve springs for this cam that are 185# closed seat pressure.