66 273 to a 65 A833 and all into 67 dart?

Ball and trunnion will be more than strong enough my dads 64 valiant has been abused for 4 years now and with a hot 360 beating on it.
Yup- even the Maxies & Hemis ran through ball & trunions. Nothing wrong with them. The biggest problem is that it's getting difficult to find rebuild/service kits for them, so most people end up going with the adapter setup now.
Hell, B&Ts are still being used on new cars, probably more so than U joints. They just call them CVs now.