No one makes a chassis for the 67 that uses C4 Corvette suspension, though you can get them for use with more modern Vette set-ups. So we had to struggle along and figure out a way to get it done!
After calling several frame places, the only one who would readily bend us tubing to our specs was Art Morrison. After tons of measuring, and talking to their engineers, I came up with bending 3 rails per side, the perimeters, the rear hump and the front kick-up. Morrison did a great job in mandrel bending the 2 x 4, 1/8" wall tubing to my specs.
I started by placing the rear humps in place. Fit the new floor and trunk floor very well, my measurements must have been right on. Before going further, we dragged in a Vette rear, and figured out ride height, half shaft angle, at rest, and relationship of the frame to the ground, and rear. My rough calculations showed the car would sit 2-3 inches too high, with things as they were. Not a lot we could do with some things, but we took a 3 way approach to remedy this.
First, we would use different bushings to bring the frame closer to the body, gain- about 1/2 to 3/4" lowering. Next, cut off the snubber on top of the Vette's batwing, would give us another full inch by mounting the real higher up towards the rails. The last inch was hard fought. Raise the rear rails 1 inch higher up. this meant cutting channels in the floor/trunk pan, and raising the area above the rear end a couple inches higher.