I had all sorts of plans for mine before I ran the numbers and realized it still had the original drivetrain in it. That changed plans, I thought it was cool and plan on keeping it 90% stock. I wouldnt go that route unless your a purist. Think about it, if you want to give the truck to your son are you gonna add those safety items like seatbelts or turn signals that didnt come with the truck originally?
I really dont think it is that big of a deal or will make any difference to the future value. Use the 261. Keep it stock-ish if your really concerned. Im doing upgrades on mine like 'painting' the drivetrain and frame. Go figure, if somebody wants to get all anal about me painting it, tough cr@p. I did a good job that will last till Im dead and gone.
What about upgrading the brake system? Another good thing if your future 16 year old will be driving it.
Think about all that before you decide what route to go. And remember WE WANT PICTURES!

By the way, Welcome to the bolt! Good luck in your project.
Jeff