[NC_John]

If you have any plans (or the possibility) that you might later install the no limit rack and pinion steering kit, use the rear holes. I had to drill a couple holes to do so on my 70 but can't remember if they were on the frame rail or crossmember.

They say the handling is improved by moving the weight of the drivetrain back, even just an inch, but I am doubtful you could notice it on one of these old trucks.