Best head for the money??

Go with the 516's since they are a closed chamber head and will give you, depending on the head gasket, between 9.5-10 comp. (fine for pump gas premium) and switch to the 1.74 exhaust valves . You may want to also look into a pocket port job to clean up the flows. You also want to be dead nuts "zero deck" which might be tough with the piston choices out there for the 383.