Engine/trans angle?
No, don't use the intake, use the crank or trans shaft or block pan rail.
Determining movement is done by watching it and measuring it's movement.
2 ways you can do it, on a drive on lift or you put a slid wire across the top, remove the snubber , use a bolt to hold the wire in place where it is touching the floor, then go and move it or tq it up, remove the wire and measure the bend.
. Optimally you want to be identical to the front angle, or 0 if you made the front angle 0 at load, but you can be within a degree or two.
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