/6 questions

Garrett Ellison said
Did you mean a 3/4 inch impact wrench? If you have air, I would see about renting an inch drive to save your back. Your probably going to have to replace ever lug stud but you may be able to run a thread die down on them first, the right direction and then inverted, to cut all the way to the nut. This works really well on axle U bolts as well. After cleaning every stud like so, put some used synthetic motor oil on them. Get some, even if you have to change oil for a friend. I’ve used everything, it’s better than anything you can buy this side of ZEP 777 or triple Z. The heavier weight, the better, used diesel synthetic works the best of everything. Wear some nitrile gloves. It surprises me that they’re all left handed and 5 lug, usually left handed on the right side in that era or size. Are they 3/4-24 studs?

Yes impact wrench. Not too worried about it at this point. Still cold out but they will come loose . I usually use anti seeze on threads and I always run a die across the threads no matter what it is, cleans everything up nice , same as I never sell a dirty part to someone.
Too bad your not closer I'd put you to work. Here's a picture of the beast
International Silver Diamond 220. I measure from back of block to center of fan blades 38" , the things about as tall as it is wide. Cant get a socket in to turn it will have to pull radiator but I did pour a mix of diesel and tranny fluid in the spark plug holes and it drained down so thats a good sign.