The air gap intake will work best with the OOTB heads...hands down. That comes from some of our dyno testing on 4" crank engines.
The M1 with porting will make close to the same HP and TQ, but the air gap will do it right OOTB!
I would add a 1" spacer and jet up 3 jet sizes (example:from 70 to 73) front and rear.