Everyone seems to be in agreement about getting the 65... surprise, surprise!
But Yachtcare touched on something much more important... your Dad is a mechanic and knows the truck. No doubt he'd be thrilled to help you out. And THAT my friend is the best reason why you want to do it!
Case in point, when I got my '56 it needed a bunch of work. I'm fortunate to have an older brother who's an ASE Triple-Master mechanic with a garage... and my Dad who's 84 is a retired mechanic. Me? I'm lost when it comes to mechanics! When I first got the truck here from Colorado, I spent an average of 10-12 hours a week at the garage after work with my brother who helped me out. In the process I learned a lot. But more importantly, I got to spend more time with him then I'd spent over the previous 30 years. And our Dad would come out to the garage and hang out as well. For him it was a treat to see the old engines he was used to. And to hang out with his sons. While I have about $5k into my Bolt (not incl. purchase & transport). She runs well enough to be my confident daily driver.
BUT the connection with my Brother and Dad is worth far more!
Do it man, do it!