Port matching question 302 casting heads

I am still undecided on exactly how we are going to build our '74 Duster and am trying to get the best idea I can of options. If I keep the 318 and build it I want to run an Edelbrock RPM Air Gap manifold so I will have to port the 302 casting 318 heads I already have so there is not a big step from the manifold to the heads. My question is...Can I just port match the heads to the 340/360 intake gasket or do I have to spray paint down the manifold while the heads are connected to a shop vac to get a paint line of where to port? Even better, does anybody have a template to port the 302 heads to so a 340/360 maniforld would work?
I do have the 587 J heads I just bought but from what my research is saying the 302 with the closed chamber and better quench are a better option if the 1.88/1.60 valves are just put in them.