The only direct 5 lug bolt ins will be a complete 71/72 rear axle if your truck is a coil spring truck. No more coil spring rear trucks after 72. I do not know about the leaf spring rear trucks.
There are companies that make bolt in 5 lug rear axles for the 67-70 rears for around $300. You can not use a 71/72 axle in the 67-70 housings, as the 67-70 rears are 1.5" NARROWER than the 71/72 rears, which may be a deciding factor for you. If you want the rear track width to be close to the front you have to run 3/4" spacers or run narrow wheels up front if you want the wheels to be in about the same spot in the fenders.
You can also pull your axles, have them redrilled for 5 lug, and have new studs pressed in.
Expect to pay $150-250 for a good rear. I just did this myself. I picked up a good 3.73 '72 rear for my 67.
