Every single 1968-up 383 has the same heads as every single 1968-up 440. All the 1968-70 engines used the "906" casting; all the 1971 engines used the universally-hated "346" head (also used on 440s through '73 and 400s from '71-'73). "Commando", "Super Commando", "TNT" and "Magnum" all used the same heads as the bread-and-butter 2-barrel motors. All 1966, and non-HP 1967 440s share the same head as the 1965-67 383s, which is the closed-chamber, small-valve "516". 1967 440s used the "915" head, which is a closed-chamber HP version of the 516 with better ports and larger exhaust valves (1.74" versus 1.60").

Yes, you can spin the nads off a 383, but it actually has a shorter stroke than a 360 so the torque is lacking. Having been in that position, I forsook the 383 for the 440's greater cubes, and never had a problem shifting a stock bottom end (including stock oil pump and pickup) at 6,800RPM.

They cost the same to build... dollar for dollar, he'll see way more power and torque from a 440.