It is the largest drop-in cam that we sell. Use with 62mm or larger single turbos or larger twins. This cam works great in 12v and 24v street trucks with stock head flow or with a ported head and stock size valves. For Common rail street trucks with larger valves and full tilt porting may we suggest the 178-208 to retain best bottom end. The intake is cut on a 99 centerline, performance springs and pushrods are recommended. If you have had your head or block surfaced, you need to verify piston to valve clearance. For it to be "drop in" on a 12v you will need no more than .018" piston protrusion and at least .055" valve face depth with a standard head gasket and a 99 intake centerline. On a 24v you will need no more than .018" piston protrusion and at least .038" valve face depth with a standard gasket. If you do not meet the minimum requirements for piston to valve clearance, don't worry, you can still run an oversize headgasket or cut valve reliefs.