I seem to have been blocked from continueing so hope this takes-
Some issues that you don't seem to be considering is that the frame is straight and level but curved-also your issue of tire rake doesn't stand because its irrelevant what the tire size is for drive line angle but amont of pinion drop from the axle centerline-the 9 inch is about 2 .5 inches and is more than any of the other rears commonly used unless its a quick change with the lower shaft being really down there.


SO--at this point I want to clear that to set driveline angle, the rear must be at a ride height setting amount on the rear travel--------the front doesn't matter-------and at this point I would have the #1 main at center level with the top of frame, a heavy wall 2.750 tube in the other mains and extended into a 9 inch rear creating an EXACT ZERO misalighnment or in other terms-bore sighted????


Now this is where I do the fabrication and will do it on a fixture, suspended at 3 points so as not to create any twist and with various tools and lazors ( great inventions) insure that the rear is straight/equal to the front end and I willfab trans crossmember and mounts for the rear end bars/arms/etc.


When the car gets assembled it only takes a small shim up at the trans mount and a little lower/upper arm adjust to tilt pinion down to get the angles------even if the car is a centered hump build with the pinion offset to the right, it still takes a degree or so up and stay in the 3 degree target range so the u joints have good life ( I only use the Spicer spl joints-no grease zerks)


This method gives my builds good road clearance for the oil pans, a pretty decent amount of room for exhaust inside the frame, room for brake system under drivers floor, and as can be seen in some of my stuff-a fuel system that is protected totally inside the frame rails.


My procedure puts the drive angles right on and first try-none of that " I've got a vibration somewhere"


I've been around a lot of builders of some very high quality stuff and learned lots from them plus of course all my own experience growing up a farm boy driving mule teams at 6 years old------


My builds have won shows, races, set national records, been in many magazines ( congrats on Cragar calendar) and besides best appearing have also won several best engineered----------