After I put my BHAF on, bumped the timing, changed the fuel pin, and turned the fuel screw in a little more, I can make the rear end of my truck start to "hop" in 4th and 5th gear when I floor it.

Am I experiencing axle wrap?

 

Id say yes moreso if you have blocks in it like my W350. Mine is an auto and does this so i put a cam underneath and filmed it wrapping up.

 

Yeah I have 7" worth of blocks. Is a shackle flip the best way to get rid of that?

 

i dont know! Try it and find out that way ill know lol. Traction bars will work!!

 

Just do ladder bars

 

Surely a shackle flip so I could get rid of most of my block would do it, wouldn't it? I don't think my springs are that soft (It sure doesn't ride like it anyway).

 

Yes a shackle flip will eliminate about 4" of blocks. You could also get lift springs to reduce it more.