318 MAX fuel economy builds?

This is what I’m thinking for my 87 truck, 318 is wore out but I have a 92 360 in great shape that Ill use the 302 heads off the 318 with the S2P2 intake, does it need that cam for millage?
No. I'm being selfish and trying to have my cake and eat it also. If I use that cam AND Rhoads adj lifters I basically get a 2barrel cam at idle and the lift and duration will increase up to about 4000 rpm. Then it's approximately full lift from there. They build these lifters to help big cam engine have a little vacuum. I'm using them as a poor man's VVT timming. I'll get 3 cam profiles from one. If I didnt use these lifters I would drop one or two cam sizes to accomplish the same mileage goals. I think I'll be around 300 hp at the crank when done. But loads of torque.