[Overdriven]

Choosing whether to run 5 or 6 lug/stud usually comes down to wheel choice and what pattern they’re available in. Me personally I’ll be converting my 67 to 5 lug when I do brakes over the winter. As far as converting to rear disc, unless you are racing the truck there really isn’t a reason to other than looks.

I don’t know by the option code what rear axle housing you have, 12bolt or HO52. I know with the 12bolt Summit has 5 lug axles available for 67-70 and probably has 5 lug brake drums and the gaskets you’d need for easy shopping. No need for anything special and all stuff most can do themselves, unless you want to change the rear gear ratio which you didn’t mention.