any truck axle from 86-95 will work for you. it is in fact 3 in. wider overall and has bigger brakes to boot. youll either need to raise your lspv to the bed floor or take it out and install a proportioning valve to still have good brakes. I have always just raised the bar to the bed and it always works fine for me. when you get the axle from the donor truck make sure you get the e-brake cables too cause they are 3 in. wider too. good luck!
WT