That head is also listed as a 230 head from 1965-70 But anyway that head Untouched had a CC of 74cc's also listed in 73-79 (250) an 75-85 (250 non-integr head)& 292 67-85 with 74ccs So you will not gain or lose anything.
Larry/Twisted6 [oooooo] Adding CFM adds boost God doesn't like ugly.