Is this engine builder nuts?

I would not spend a dime on 273 heads, for the $ you spend the return is not there. After machine work and paying someone to port them and buying hardware, You would be farther ahead with a set of the new RHS or similar heads. Already has big valves, closed chamber and will flow more unported than any ported 273 head with bigger valves. Nothing wrong with a 318 to build up, just that it costs the same to build a 360 and in the end you get more hp and torque for the same $.