Revs up fast and pulls hard in engines with big bore cylinders, modified cylinder heads, intake,compression and exhaust The Reaper« 538 grind will shine in 124ö and larger cubic inch engines with added compression ratio The stock throttle body produces an excellent powerband and use of a high-flow throttle body will increase peak power numbers Ported cylinder heads are not required, but will complement the cam and add even more pulling power throughout the range A high-flow exhaust system and air cleaner is highly recommended for optimal performance 2250 - 6250 rpm range. CAMS 538 REAP M8 CHAIN DR