This is the baddest roots blower made, period. It is the 18-71 equivalent with our high overdrive top plate attached to it. This enables it to be turned in the mid 40% overdrive area. Testing has produced boost numbers in the high 40 psi area. This is the ultimate choice for Outlaw Racing where a screw blower is not allowed. Blower comes complete with your choice of top plates, snout and 14.2 restraint.