[68 TT]

From what I understand the best source is a complete setup off a diesel truck or SUV. Not sure what years are the best. 88-93 NBS uses one design and 83-87(91) square bodies use another. I would go with the one that has the same accessory drive system you want to run, V-belt or serpentine and grab that whole setup to match.

An Astro van with the optional hydraboost is a second choice but may need a different master cylinder to work on a truck The one I was looking at a couple days ago was angled downward pretty heavily. It would cause fluid level issues in the brakes if mounted level. The hoses are bound to be all different too so that is more added cost.

I believe a keyed firewall plate will be needed to keep things from rotating. You can make your own, cut the piece from the donor or buy a prefabricated part from one of the vendors out there.

You need the power steering pump from the donor as well since it is an integral part of the hydraboost system. I would assume the power steering brackets are unique to the hydraboost power steering pump so make sure you get those as well.