Just bought my first mopar. Looking for help!
56K on it. That 318 and A904 aren't even broke in. Not sure what your budget is, but I'd recommend get the 318 and A904 up and running and drive it with that while you upgrade your suspension, wheels, brakes etc for what you decide engine and trans wise later. You can always sell the 318 and trans later on. If body is straight, you can always scuff it down, and prime it with 2K epoxy primer to seal it up and make it look decent while working on the rest.
A stroker small block or big block is both your choice. I'd recommend a 360 bored and stroked to 408 as it will be the same dimensionally as the 318 coming out, unless you just need the wow factor of a big block.
Unlike Chevy stuff, if you run a mopar big block, you need a big block trans. The bellhousings do not interchange with small block.
Another recommendation is upgrading to the later style big bolt pattern. It upgrades to 1/2" lug studs. More readily available brake parts and rotors which go all the way up to 1989 on chrysler fifth avenue, dodge diplomat. The pattern is 5 bolt 4.50" circle. If your car has 10" finned drums on the front, you likely already have the bigger balljoint upper A arms. All you will need for the disc brake swap is everything from the spindle out from 63-76 disc brake A body.
If you have the smaller ball joint upper arms you will have to get the bigger joint arms, or a sleeve kit from Doctor Diff to run the smaller joint arms, Or tubular upper arms. You will also need the 73-76 A body lower ball joints for disc brake cars to do this swap and 4 grade 8 bolts with stove nuts to attach the lower ball joints to the disc brake spindle. It all seems crazy to describe it, but it's all a pretty straight forward swap.
What's on your car currently appears to be a 5 bolt 4 inch circle with smaller 7/16" studs. This pattern is really hard to find decent aftermarket wheels for. And the left half of the car, your lug studs are or should be currently left hand thread. Stud center will have an L or R stamped into it for direction of removal. Change that **** to all RH thread.
Personally I am a fan of wide black painted 15" steelies, black walls, and chrome lug nuts, along with grey primer bodies Cheap and good looking IMHO, I must just be a cheap *** and put my cash into other things
Remember that anything you pull from on this car because of an upgrade has value to somebody else here building a mopar. Do not toss your cast off parts, post them here on Fabo for sale.
I recommend looking at the different build threads while you get it running and driving and sort through it. My build thread on the 67 cuda i own morphed from edgy but street legal asphalt circle track car on the street to a restored sleeper. Plus I pulled the car apart 10 years ago, and it still isnt together.
Sorry if this is a long list I have typed. Good luck with your dart. It's one of the cooler looking years, and in good shape. Hope to see you around here more, and be able to help offer advice. Lots of ideas offered, and a lot of directions to go. Get your feet wet, and read a lot of the build threads, make notes. I have copied pix of ideas from others cars and put em into a file called "cuda ideas" in my phone. I use that as a reference library on the go.There may be some ideas you like you never thought about doing.
Hope this helps
Matt