here are some #'s to look at.if you are not going to go over .500'' lift on the cam 5c's are better,but if you are going to port the heads and go over .600'' lift find the 6x.
these #'s are in the right place.
port volume, 5c 151cc int./138cc exh.
6x 158cc int./146cc exh.
bigger exhaust valves
flow#'s at .500''