Welcome from Virginia. As others said buy the most complete car you can. Take your time when working on it and do it safely. Download or purchase a service manual. When you need help ask the community. We have all been there before. Post pic t uses of before during and after. We all like eye candy.
That swap made a lot of work for you. They aren't hard to change but then you say "I'm going to fix this while I have it out" and then you see all the other things....
Tried Advance Auto or Richard Eberg on eBay? I got my cable from Rick and a couple of other things I couldn't find. Emailed him about a 3 pring reverse light switch and he dug one up.
Link to his store.
https://ebay.us/m/E8ZYup
Leave it stealth. Make them guess it's what I do. Mine says 340+6 but I make them guess what that means. Big block buddies of mine hate me because of it.
High volume oil pump and 50W oil is what I run in my 416. Don't use a Fram filter. Get a quality one built for higher pressures like a Moroso. My pump sucked my Fram filter inside itself. Won't use another one.
I thought Cuda and Challenger ones were slightly different. Wonder if they sold you the wrong ones. You could probably pull that in gently. We had to do the same thing on the rear of a 71 Charger 500 we worked on.
Just did the PST upgrade in March. I am pleased and I upgraded to the solid tie rod sleeves. Made the front so tight that now I notice the back end wiggle. One stop shop. Got new upper control arms and had the ball joints pressed in before shipping. Got 10% off as well from their ad link here.