1967 Dodge Dart Post

I've been lurking on this site for many years. I live in the SF Bay Area and I have a 67 slant 6 Dart Post that I drive about twice a week. The car is completely bone stock. It runs great. I want to begin to upgrade the vehicle from suspension, motor, brakes etc.

The problem is I don't know where to start. What part of the car do I begin to upgrade first? For example, should I convert to big bolt pattern first? I would like to continue to drive the vehicle I don't want it out of commission for a long period of time.

My idea for the car would be a street machine. It doesn't need to be a world beater although I would like to spin tires. Maybe a traffic light warrior? I would probably take it for long drives. Horsepower and torque 250-300HP, not really sure about operating range of torque.

From browsing the site, it seems the consensus would be:

Motor - 318 or 360 LA or Magnum

Trans - Overdrive 200r4 or Gear Vendor

Rear end -8 3/4 with 3.23 gears

Rebuild or upgrade suspension.

Not sure where to start first. I really want to keep it simple. Any help would be much appreciated. And thanks to everyone who contributes to this site. You all are some very smart people who could easily have mechanical engineering jobs.

Norm