I'm trying to put disc brakes on my 69 521. Looking for some lower control arms and the uppers from 78-79 620. Is there anyone that can help. Can't find any, I've look in eBay and there is someone says they have them but then there is a picture of a 720 so I don't think that will work. I got all this info from one of the forms in here and those are the only parts I need. This truck is going to have air ride so I have to most die everything. Thanks if anyone can help.