any benefit to swapping heads?

Read the first page... skiped to the third
and noticed people were missing things about the small valves and velocity potential... hell I can have a 1.92 flowing 255 cfm easily , what's that worth against the X 2.02 that's only does 218- 228cfm as cast "given the best casting you can find". More mixing after the carb.

I know if it were me I would probably Port the X and swap them on. You can get about 265 to almost 270 cfm with a 3/8 valve stem and conservative porting, no major guide work.