69 camaro rear end travel help!

[David Pozzi]

I meant 6" total travel bump & rebound, so 3" of available bump travel with maybe .5" more lost to a coil over bump stop, leaving 2.5" bump travel before you hit the bump stop. With shocks behind the axle it translates into a little less travel at the axle centerline due to the motion ratios.

3" at the axle is pretty good. Be sure to check your pinion bumper & driveshaft to tunnel clearence. If your trans is angled down to the rear, it will require the pinion to be angled up the same amount to align it, this can cause the driveshaft to be higher than you might think.
Those frame rails do look like they droop to the rear.
David