75-76 400

Would it help or hurt the 400 by putting 2406516 heads the the engine. This casting number shows that the head has 2.08 Int and 1.60 Exh valves and is a closed chamber head. Used from 64 thur 67 on 361 - 383 - 413 - 426. The reason I'm asking is that I have a fresh set of heads that have been done with harden seats. Thanks Ron