All xheads are 2.02/1.60, not all J heads are unless you've paid for valves and machine work.....so I'll go with X head value being higher. Better valving from the get go. More potential so to speak.
No sir. Some J heads came with the bigger valves. We said the same thing. Certainly the factory 2.02 head value would be higher for the resto crowd, whether it was the X or J.
