Some photos of a subframe job my buddy did.
http://s173.photobucket.com/user/mr4...?sort=4&page=1
NOTE THOUGH!!!! this truck was intended to be in the weeds low.
I found out a long time ago that to get your rig to set exactly where you want it height wise with a subframe job you have to set the remainder of the frame level at the exact static height you want it to sit at (it has to be level because you want the completed frame to be straight without a bend in the middle you do not build in rake in the frame)
Then you block the subframe at real close to the exact ride height that it rolled around in the donor rig. That may take sliding under a similar rig to the donor and measuring the distance from the bottom of the crossmeber to the floor or ground. We did exactly that with a student's Nova when we put the Nova subframe under my 51 Merc and it sat perfect and drove fantastic.
We sat the front crossmeber on a piece of cross tie when we did the Merc and leveled the rear legs of the subframe to match the stock frame. We used a rear steer subframe on that one though and those work great on those Mercs.
At any rate the rear legs of the subframe and the stock frame rails have to be on the exact same plane no matter what the ride height is. The subframe should sit exactly as it did in the donor rig as far as level front to back.