68 Cuda 383 vs a 360

The starter is a nice plus for sure.
Spark plugs are a really nice plus for sure!
Can set up is tight but should not be a problem. The fan clutch (if your using that style) is available @ Hudson, they have what they titled the “Muscle Car Short fan clutch.”
Transmission bolts are @ the hardware store. (Use grade 5, grade 8 a plus!)

The real bear is hooking up the trans to the engine with the engine installed already. Getting your hands in the back to install the attaching bolts is already a bit of a PIA with small block.
I always removed and installed my 440 in my 69 cuda with the engine and transmission together. Heck even did it without removing the hood. My car was an original M code car so the engine size wasn’t an option for me but at the time I also had a 69 340 Survivor. If I was building a car from scratch I’d go with a 360 with big valve 340 heads. I had a stock 79 Little Red Express with this combo and it was quick.