xr200r head on a 200s

[Mudder F er]

Im thinking of getting an xr200r head with the cam, valves, and timing gear, etc. I want to put it on a 200s lower end. My question is will it make a difference in speed, and will it just bolt right on, or will I have to make any changes or adjustments to either top or lower end? Or if anyone has any other recomendations of what I can do for a little extra speed. I have to change the cam and probably the valves anyways on my s engine because they are frozen. Thanks

[Mudder F er]

or is it best to just use the parts from the xr like the cam.

[speed20]

im almost positive that the top end on a 200s is the same as an xr200 motor (1981-82 i believe) i had a 200x (1984) that had an xr 200 motor on it, and the parts were interchangable....as for a speed difference....i do not know....