I don't own a vehicle that even knows what connecting to anything besides an OBD2 scanner is!! My newest vehicle is 18 years old. Oldest is the square at 42 years old!
Satellite antennas can be little puck things stuck to a roof? Ever seen a GPS antenna for a held held unit? Ever seen a boat GPS antenna, there like round bowl things. Ever seen a satellite radio antenna, the one on my wife's care is a little magnetic puck like about 2"x2" and not an inch tall...
It's been so long I'm not sure what exactly we're debating. But you could have an 80 with round headlights....but it for sure is the only year with single large square headlights.
I bet it's the tranny. That trans should easy start out that light if a trailer. A 383 with 4:11 should be able to burn out with that trailer sitting on that truck.
I can pull 9000+ pounds of firewood on my trailer with .h 350/350/205 combo with 3.08 gears and 33" tires!! It's not fast to speed...
I think it was late 80 or 81? Well your probably right. My truck is an 80 but it's not the original block and who knows what it's out of. I have the older style and a two piece rear main.
Are you sure it's the correct gasket? There two styles, one for the different pans the older style and newer style. There is different size humps for different year blocks.
If you don't drive it much and high speed drone won't drive you crazy I would cut it all off before the mufflers and just put turndowns and hangers if you need them to keep the pipe still. It will free flow more and be cheaper and you will be done with it. You probably have a lot more pipe that...