Not to long ago, I did an axle flip on the old truck to lower it, and also used drop shackles. The axle was originally under the leaf springs, now its rests on top. Ever since the flip, If I "accidentally" break traction, it starts to hop really bad. It starts off spinning, then begins to hop so bad it feels like something is gone break..any ideas what the cause would be, and what can I do to prevent it??

Is it possible that the driveline angle is out of whack? This could cause voodoo harmonics due to an incorrect pinion angle.

Yikes..I never really measured..I basically eye balled it..I didn't really think a few degrees would matter much..

when you did you flip remove any leaves to help in the drop??

This is gonna make me sound like a tard... how to I properly measure my pinion angle?

I wanted to point out also, that under normal and even HARD acceleration, I have no unusual vibration or harmonics..this happens ONLY when I lose traction.

you need more HP to keep them spinning.

You could try clamping the springs in front of the axle. Do the shocks have plenty of travel?

Yes, BUT the axle does not have much room...I think maybe 2 inches..is it possible that the truck is squatting hard enough to sit the axle on the frame, effectively canceling out the shock absorption of the suspension?? That would definitely cause axle hop wouldn't it?

This is my cleareance, axle to frame. This is as it sits, on the ground, does this cleareance look adequate?

This is just spitballin' here, but what if your shocks have a dead spot in them? I have seen and OWNED some shocks that worked fine in most situations, but when I removed them, they had some free play in them.
Also, Is it possible that you have NO pinion snubber and the axle radically ROTATES when the tires get a good bite? Basically, the axle yoke where the driveshaft connects tries to go up and down rapidly? If that is the case, maybe a fabbed up pinion snubber would help.

Hmmm...come to think of it, I fairly certain the truck never had a snubber to begin with...maybe a tabbed snubber as you suggested coupled with some traction bars to help prevent the leaves from trying to wrap? Anybody gotta pic of a typical snubbed/mount location?

as you said, trucks dont have snubbers. you will have to fab something for the snubber to hit when you launch. Does you axle even have the holes to bolt a snubber to? Personally Id run some slapper bars for the old school look. They are very easy to build.I would take the old spring mout off for more clearance..