Hi There bnw,
I installed mine while the tub was on the Chassis. "No Hickups" at that point. My Engine was out of the car.
There is about 1" of space between the Block & the Arm & It would be a Son of a Gun to install with the Engine on the Frame. The "Roll Pin(s)" would be a bit difficult to hammer down in there.
"HAVE FUN",
Russ