Who wants to play; Find the problem?

[Chris(NJ)]

Here's where I'm at. About a month ago S*** hit the fan w/ this truck lol. Seems like everything happened at once and I find it hard to believe that that 3 separate problems occurred simultaneously. So if I was a betting man, I'd assume they're somehow related. But knowing how bad I am at gambling, they're probably not related.

Overall, The truck has been pretty flawless over the past 14 months. So it's not likely a tuning issue. Motor is a crate 350 w/ a th350 trans. Ran the edelbrock carb serial number and came back to a 750cfm, (1407)

I noticed a slight stumble driving it to a cruise night. I thought maybe another arching plug wire, maybe some bad fuel...but nothing that grabbed my attention enough to think there was a major problem.
Leaving the cruise night things got bad quickly. I thought the truck would die and kept putting it in neutral at stop lights in fear of it stalling.
Limped it home and parked it in the garage.
Pull it out of the garage a few days later and you can see the mess it left on the ground. Both trans and engine oil leaking.

The engine problem is definitely worse in gear. Reverse, drive, etc...it runs, but barely. If I step on the gas, it really doesn't want to move. but idle doesn't seem THAT bad. I guess it's all relative. When we had warmer weather, It also seemed to get worse as it heated up. No scary sounds either. Engine itself sounds smooth. No knocking, tapping, etc. It's just...missing.
I pulled the distributor since it's been over a year of driving. I wanted to see how it looked, and figured I'd replace the ICM while I was in there. Read that can cause similar problems to what I was experiencing, but no dice. Unchanged. Spark plugs looked fine from what I can tell. No major tell tale signs of a problem.

Ideally, If the problems aren't related, I'd like to fix the flat-on-its-face stumble first. Because I can always add oil to get it to a mechanic and if there's a few leaking seals, that's going to be beyond my capabilities to fix anyway.

I know this is almost like taking shots in the dark, but I'll take any advice I can get.
Believe it or not, this is my first carb'd motor. I've always worked on modern engines, and I'll never underestimate the value of being able to plug into an obd port and have a computer tell me what the problem is

Old pic of motor, but nothing really different.