What is the best stuff out there to remove all the original paint?

Aircraft Stripper - You'll find (or have found) a plethora of paint strippers on the market. And asking fellow customizers is likely to yield an equivalent amount of suggestions. One of the ultimate stripping solution , is Aircraft Stripper. Chuck (from Southern Kustoms) and many other contributors swear by Aircraft Stripper. So what is it and where do you find it? Well, to answer the first part of the question, Aircraft Stripper is not always a "brand name." That is, there are different manufactures selling aircraft grade stripper. But all varieties seem to work well. What to look for are the words "Aircraft Stripper" plastered somewhere across the front of the container. And the first place to begin your search is at automotive supply houses such as: Pep Boys, Autozone, Napa, etc.. The aircraft grade stuff is not usually found in Home Depots or other hardware stores, but it never hurts to check.

from: https://www.hotworldcustoms.com/strip.htm

Yep, Kleen Strip Aircraft Stripper. Comes in a light blue can. Brush it on in ONE DIRECTION ONLY, let sit for 15 minutes, and most, if not all, of your finish will come off. May need to reapply to get stubborn primers to come loose. I use a brass brush for the corners and the joints at lugs.

Wear protection too, chemical gloves, long sleeved shirt, pants, safety goggles. That stuff is nasty.

yeah, be extra careful if you have any pets. make sure not to spill any of that stuff.

i strongly recommend the spray-can jasco.

sandblasting would be the best thing (less health hazard) but if you are into that sort of thing buy a can of xylene it takes the paint right off.