The Caddy kind..... and I need input from some caddy experts. The motor is a 1956 365. One of mine is beyond repair and I need to find a set. From what I've gathered so far, in my research, the 56 heads came in two versions. Early and Late. I believe I have the Late version. Also heard that later 390 heads will work but I need to buy in pairs due to combustion chamber volume differences between years. I may consider a 61-62 390 swap if I can find a good motor. Any help appreciated.