[Red Mustang Gt 46]

In reference to porting 96-98 heads, with all the time and effort, a set of 99+ heads would net a greater amount of HP with minimal effort and cash. BTW, the valves are tiny...smaller than valves on a HARLEY...really.
With a port job on the 96-97 heads, the shroud near the exaust port would be removed, lowering your compression.