Lots and lots of successful Ford powed Pietenpols. A motorcycle on a Pietenpol is easy to change if you are not happy. Being close to Broadhead and surrounded by Pietenpols where I live I've seen quite a few and have had pretty long conversations with the owners.
No matter what you put it you'll be happy. You're not building a cross country traveler or a Reno racer. The little 65's are definitely great, same with the Ford, it depends on the type of personality you have. Either way, it's a cool set up.