I feel your pain. I had a Charger BB that had a similar problem.

If you are going to replace it with a mini-starter then do like CYACOP suggested and disassemble the current starter in the car.

There are two 3/8" bolts on the back Remove them and the rear comes loose. You can move the rear housing back a little and another bolt will disconnect the field windings from the front half of the starter.

The armature is long but just slides out and since you are going to replace the starter don't be afraid to cut anything that is tying it together.

As for the best Mini Starter I have been using the later model mopar starters from the 90's. I'm sure other people have a better brand.

If that doesn't work then it looks like unbolting the header from the exhaust and cylinder head may be the first step. I also had to loosen the motor mount and raise the engine and unbolt the power steering too, just to get it to move out of the way enough to get the big starter in or out on my old Charger.

Good Luck.