We have actually thought about an LS powerplant in our Sunbird. Picture below is mock up. We decided to put another small block in it since the exhaust was already made. It is a tight fit. You'd be hard pressed to find a set of headers that fit, but a set of manifolds would probably work if you modified the steering as we did. I agree with everything you are saying on the Ford vs. GM stuff.
My sister had a 75 v8 coupe. I was not a huge fan but it moved well. The gas pedal was strangely 5x harder to push than the power brake pedal. Some weird gas saving method? Anyway changing plugs kinda sucked, but really you just unbolted the engine mount and then jacked the engine a couple of inches to get to the tough plugs. Now headers and plugs on that car might require alcohol consumption.
The stockers should be fine for my application. Thank God.