I have no Idea where to start

Ok, first, this is a long journey, not a quick trip. Plan your build now and stay firm to your vision. If you’re truly set on a big block, then set yourself on that road learning what that means. It’s heavier than a small block, so heavier duty items are needed in driveline, things that are not factory parts. Being that you already need front end work, that would be the time to put your big block plan in place there. Larger torsion bars, new joints and bushings on everything, maybe a sway bar, shocks, everything you do now should reflect your vision of the car.

Since you are a spreadsheet guy, go through every aspect of the car, write areas down by category, then break down every part that needs replaced in that area. Interior for instance....front seats, need covers, maybe foam, and tracks. Door panels?...color, availability, price, originality or aftermarket? Headliner, dash pad, package tray, seatbelts, carpet, armrests, handles and trim. Take stock of the parts you have, what could be done to them to refurbish them to save money, and how and where to get stuff you need. Then come here and ask questions...”where can I get _______ for my 70 Dart?” Then visit websites and build a price sheet for every item and where to get it.

Then take one area at a time and concentrate on that based on your research, the car’s immediate needs, and your long term goals!! Boom, $1000’s of hours and dollars later, you will have your prize!!