I have a 1967 350 4 speed i bought bare bones. I was told the rear axle in the car was incorrect. Not a problem, I have a complete (bolt-in ready) 8.5" 10 bolt from a 71 Nova. 2 Issues here: 1. I Removed the old axle housing, rear springs, spring mounts, shackles, etc. I cleaned the springs, installed new bushings and shackles and re-installed the rear springs. By the way, I am using a multi-spring set-up. I don't know how to line up the new axle housing to the springs(The perches are there and have never been removed). Should I use the original wheelbase figures? Or are there some points of measure under the car that I can use? 2. How do I know what my driveshaft length should be? Seems a bit tight under there right now without knowing where everything bolts up? Thanks.