I've got a D70 under my ambulance. It has 4.10 gears and some type of posi, this is a dually. Is this unit as strong as a 14 bolt FF. I am thinking about parting out the rig and keeping the rearend for future projects. Is the 14 bolt easier to get parts for? I read about alot of folks switching over to the 14, but hardly ever anything about the D70-whats up? Also, what's a good D70 going for out on the market?