first a dooe head is 1970 c8 would be 68 the 70 head 65cc i think only289 heads were58cc and if they are58cc you do not need to cut them unless you need more than 10:1 compression. i have a set of 68 or69 302 heads professionally ported by champion head service in jax. with windsor size valves this is the best chamber design for flow of the older heads if you want stock type heads .351heads flow better than 302 heads 69 351 heads being the best. but the chamber is bigger losing comp. unless milled.i also have a set of 289 heads. all are for sale cheap. 352-666-4575 barry