Is it true that the 84 and later model heads have bigger intake valves than earlier models? Thanks

83+ actually. The intake valves are 2mm larger. The published HP numbers went up by 1. Not even noticeable in the real world and definitely not worth seeking out unless you need to replace your heads anyway. And in any case a good machine shop could enlarge the valves on 80-82 heads to match or make any of the heads larger even than the 83+ heads.

 

GD