General Slant 6 Input Required

I'm down at 39th Ave and Thunderbird.

It's a 75 Duster. Will be my daily driver when I am in town. So I am looking for gas mileage and a bit of zip. If I can squeeze out 125 - 150 HP I'm OK with that. I am just brainstorming but what I would like to do is:

Upgrade to a 2BBL, so I am looking at getting a Super Six Intake. Probably stick with a Carter. Aluminum/Cast I haven't decided.

Given the opportunity I'll pull the head and have a proper valve grind done.

Mild cam. Maybe in the .425 - .430 range.

Exhaust undecided. I want to dump as much useless crap off the engine as I possibly can. Heard/read many opinions of exhaust pros/cons. Dutras seem OK, but pricey and heavy. Headers, not cheap, better weight but durability issues. I think EGR is a waste of time.