Try looking at Clifford performance. With their intake and carb or carbs if you decide to go with the duel carb setup, you can fashion your own wiring harness from scratch.
Yes that will work also but the supports will probably have to be on each side of the plate so it can be removed. One support near the plate may be fine you will just have to try it.
If it’s still stock, spring is under axle so loosening the plate will cause the body and spring to go down away from axle. The tires can remain on the ground, but the body needs to be supported to keep it from lowering as you loosen the U bolts.
Check all the steering linkages. Tie rod end and ball joints. Also steering shaft u joints. The bottom steering column bearing is the one that goes bad the most.
I have used a length of chain from the rear head bolt stud to one of the pressure plate bolt holes. I use a longer bolt in the pressure plate bolt hole and the chain keeps the engine from turning while torquing the bolts. Still have to get the flywheel up on and bolts started, and that sucks.
Yes it is a lot to do. And I do have quite a bit of 1 1/2 x 3/16 angle bracing holding the shape as much as possible on the top side but on the lower side it would be in the way and just make things too difficult. Your way is the best if you are able to do it. But I have done everything by...