LOOKING FOR ADVICE

Im looking for some advice from guys who have been through this before. Im not sure which direction i should go with my car. ( here's backstory on my car) I bought my 74 Dart back in 07. Daily drove it until i sold it in 2013. It is a deff. project car and i wasn't able to do much more than minor repairs while i had it due to time and money. I was able to repurchase the car in Dec 2016 in much worse shape then when i sold it. So here's my dilliema, car needs floor pans, some roof repairs, lower quarters, trunk patch, paint, interior redone. Right now cyl head is off the engine and needs valve job. I have most parts to reassemble engine and get running again. Its a slant six (which i dont want) i picked up a 99 5.2 out of a durango to swap into it. My original pan was to replace floor pans , drop k-member out and paint engine compartment, gather parts need to complete magmum swap. Now im thinking to get slant running and enjoy car for awhile while i attack small projects on it. Worried about tearing car down and it turning into multi-year project that i dont get to enjoy. Sorry for long post and i appreciate any advise you can give.
Thanks J.R.