The M1 ports will be bigger than the 318 ports. The Edelbrock Performer has ports that match the 318 pretty good. I have one on my 318 in my Duster and in your case it would be a good one to use with a stock motor. You can put either a square bore carb (Carter, Holley) or a spreadbore carb (Thermoquad, Q-Jet) on it. I have a Q-jet on mine and I get 17 - 18mph combined.
Chuck