Three on the tree options

Being you have no transmission to start with I would go with the 230 but it will also require a driveshaft because 65 still has a ball and trunnion drive shaft. I am pretty sure that they came in column shift, but you may have to modify the shift rods, speedo cable would require being updated. Not sure on the driveshaft but a 66 Dart would be a place to start. A 65-66 slant six 4 speed bellhousing would work with the clutch bell crank parts from the original car.