[68 TT]

What rear end is in your truck now and how much does the truck weigh? What rear suspension is in your truck?

No point in putting a heavier rear axle into it than you need and slowing the truck down in the process.

Chances are the stock 67-72 truck 12-bolt with a set of good axles, big bearing housing ends with press-on bearings and a spool (or good clutch type posi if you street drive it too) will take more power than you are making. It will lose less power to the wheels due to pinion location vs. a 9" and will weigh less too. The Dana 60 is overkill and weighs a ton more.

I know a 3200 pound car that has been running high eight second quarter miles for years with a car 12-bolt so it can take quite a bit of power. With the truck 12-bolt the smaller pinion diameter will be your limiting point but not too limiting. I would bet it can take 3/4 of what a car 12-bolt can due to it. If you have about a 4000 pound truck and 800 hp or less it should be OK.