if i do it and use the 3 washers how far will the back have to come down to sit level?

 

BJ ususally is documented at .75-1 inch downward. otherwise if you want the back actually level grab a ruler.

 

so a 1 inch block in the rear should get it close enough then

 

you could use a 1in block or pull out one leaf so theres only two of them

 

I done a bj flip with 3 washers. And put a set of 2" blox on back. Looks great rides way better!