These heads are welded and cnc ported with 1.900" intake valves. The ports get choked down 30% for max torque which drives the bottom end torque up quicker and the greater velocity in the exhaust ports aids port scavageing. Tested against other non welded heads in a 1:1 ratio dyno pull in real time they rev 2-3 seconds quicker.

 

Depending on displacement and power requirements desired, the RR615 (10.8:1- 11.2:1 torque cam for smaller displacement engines), S&S 525 (10.8- 11.2:1 torque cam for larger displacement engines), or the S&S 640 (11.5 and up compression horsepower cam for large displacement engines). The stage 5 will give more torque and horse over the welded stage 4 but the torque comes on 6-8 hundred rpm's later than the stage 4's. The stage 4 welded heads sometimes get used on 117" baggers with great results.