I installed the dual coil speaker last year in an E-body dash. Thankfully I had the dash out of the car.
There was not enough clearance o the backside to drop the speaker in. I had to do some mods to the speaker chassis and mounting hardware to get it to fit without having to cut into the dash frame (others have).

My original radio was gone so I replaced it with one from classic car stereo that looks OEM, but is modern internally.
That took car of the ohm issue.

https://www.classiccarstereos.com/1970-71-mopar-e-body-radio-chrome-buttons.html