The 440 will need all of its accessories and pulleys etc...If you want to use the original wiring harness a few mods will need to be done but honestly the harnesses are a constant problem on an old Mopar. After 50 years the insulation gets hard and is prone to cracking. Grounds are corroded...
Remove the sending unit and test it before you start buying a bunch of parts. They are a very simple mechanism and it could just be a poor connection causing the wide fluctuations and might be repairable.
If you are talking about using the stock, slapstick shifter.
Here is a link from another Mopar site.
The shifter will work but the trans needs to have the shift levers swapped from the 727 to the 518 for it to work. It is covered in this link.
727 to A518 swap a novice guide.
Not too many intake choices. As far as the angle of the intake bolts, a good vice should be able to bend yours to 90° fairly simply.
Mancini does stock several brackets, not sure about the Magnum intake though.
What I see in the picture of post #24 is that the belts are not routed properly.
The problem is with the water pump pulley.
The alternator and a/c compressor have dual groove pullies because when the a/c clutch is engaged it puts a large load on the belt and it will slip, so it needs 2 of them...
Check the upper and lower mounts for bends or damage first, then proceed.
Unless the car has the stock suspension and new, factory spec springs, your rear ride height numbers are really meaningless.
Just like front ride height numbers. The factory only did it one way. Stock/stock/stock...