my data plate shows a 19 for the axel code on my 90 f150, I thinkthis means a 3.55 open defferential, can someone comfirm this. I have a 3.27 posi out of a Mark 7 that I would like to put in. It should help some on the gas and not take to much away from the pulling power, plus give me a posi unit to boot.

 

Yes, that's a 3.55 open.

 

Check your other thread.