318-3 Closed Chamber Truck Heads

Can I ask why you would want to use those heads? I get close chamber heads raise compression, but close chamber heads don't flow as well, and that old of head would not have hardened seats.

I want to use them because I have them. Alternatively I will just use STD 318 small-port open chamber heads which have the same flow characteristics/restrictions.

If I use them I will have the seats done, just like I'd have to on any LA cylinder head available in Australia.