73 Dart Swinger - Need advice!!!!!!!!

Skinny tires,An LSD,And a turbo,done.
You got a $12,000 dream and a $3000 budget.OOps, that's 12000 Can, lol, about $9000USd.
And some of your goals are unrealistic;
Like 4.10s and hiway cruising. Like Hi-way cruising and lite to lite rubber.
Double OOps 3Gs for just the engine/trans, my bad, I missed that... so I better start over...................

For your stated goals, I's say:you need either
A) a big engine to pull a hiway gear, and enough stall to break traction,or
B) a smaller V8, with plenty of low rpm torque, an overdrive and whatever gear lol., or
C) some form of supercharging ....... on the slanty, or on a junkyard teener. These projects have a way of stretching time.
D) 360LAs/5.9s are easy to make power with. This does not mean cheap. But a Magnum already has a better Stock compression ratio. This doesn't mean much, if the pistons are gonna be replaced.

Trailbeast has the skinny. Clone his program and you will be as happy as he is.
EFI is icing.
If you wanna go stickshift, you can clone mine.
If you value fuel mileage, there are a couple of happy 273 owners here, but um you're gonna have to pick either/or...hiway or burning rubber.
A 318 needs to be biased one way or the other
A 360 with a small cam, can easily do all three. Sometimes/often/almost usually, without an overdrive.