Congrats on the 60 (we're all dying to see a pic of the actual truck BTW) and welcome to the world of keeping these things on the road! Reading though the whole post was like having a flashback. I think @NeverGiveUpYota, @Gretsch, @g-man, @Spike Strip, and a few others could all attest that I was going through all of the EXACT same issues a little over a year ago (thanks for all the help along the way). I think Yota gave you the best advice so far, in her response about the tailpipe discharge, yet it applies to all these old LCs...."Don’t make yourself crazy being hypersensitive about stuff...". It's a 34+ yr old vehicle that is lightyears behind what we'e used to driving now. Don't always assume the worst...I wasted a fair bit of $$$ doing that early on...start with the simple and free things first. It sounds like the fuel tank swap has helped you overcome the biggest hurdle; just keeping it running in order to be able to diagnose other things. Based on what I went through, here's what I would suggest based on the areas of concern you've mentioned:
1. Running warm/hot...what makes you think it's running warm? I ask b/c the owner manual shows the "normal operating temp" on the gauge to be anywhere from about a 1/4 up the gauge all the way to the left edge of the red line. It took me a while to just accept this. Long story short, I replaced my WP, t-stat, & hoses as a semi knee-jerk reaction to what I thought was a hot engine. I do not wish this job on you! Even after all that, it only lasted about 2 days and then I was "hot" again. The real problem was small leaks at hose connections that was 1) not keeping the system pressurized and 2) when warmed up, allowing air into the system that was then collecting at the temp sensor so it was sitting in a pocket of air and just reading the heat transferred directly from the metal.
Get yourself an IR temp gun if you don't have one and shoot temps from around the block when it's getting "hot". At least you can then see a temp and decided to be more paranoid or not. I still have a certain level of engine temp PTSD from going through that episode. Then go through and triple check that all the hose clamps are snug. The ends of my upper and lower hardlines on the PS of the engine were rusted through where the hose clamped...that's why I couldn't keep pressure. I was able to cut about an inch off and reconnect a slightly longer hose.
2. Exhaust leak: What specifically is making you think you have an exhaust leak? It was a periodic exhaust smell with the hood open, loud engine, and bad idle for me. Turns out it was the connection of the manifold downpipe and exhaust pipe. The garbage aftermarket gasket had burned up and the nuts had loosened at the connection. 1 OE all metal gasket and 3 tightened nuts later it was done.
3. Rough idle/couldn't get idle below 1000rpm: There is a small metal tube that is molded in the heat riser under the carb. My riser was cracked where the tube goes in. A little JB weld to seal it up confirmed it was the source of my issue and shored things up until I could get a new carb plate delivered.
4. Tailpipe discharge: Mine did the same thing for a bit after I worked through my carb and fuel issues. It just stopped eventually, but not before blasting my toolbox and storage shelves when I backed into the garage the first time it did it!
5. GET A COPY OF ALL THE FSM RELATED PUBLICATIONS!!! Last I looked, the resources "library" doesn't yet have all the stuff that was available previously. We'll figure out a way to get you copies...hell, I'll put it all on a thumb dive and mail it to you if you want.
It's not the most exciting to look at, but get the emissions manual and personally check all of your vacuum line routing and connections. I ended up finding an incorrect connection that solved a hesitation I was getting when accelerating from a stop.
6. A/C: What makes you think the compressor is bad? I thought my A/C was going too, but I ended up adjusting the tension on the belt and re-charging the system and it works great now. If it really is going out, check RockAuto. I was surprised at how many OEM parts they have on there and for very reasonable prices. I know they have all the A/C parts.
1. Running warm/hot...what makes you think it's running warm? I ask b/c the owner manual shows the "normal operating temp" on the gauge to be anywhere from about a 1/4 up the gauge all the way to the left edge of the red line. It took me a while to just accept this. Long story short, I replaced my WP, t-stat, & hoses as a semi knee-jerk reaction to what I thought was a hot engine. I do not wish this job on you! Even after all that, it only lasted about 2 days and then I was "hot" again. The real problem was small leaks at hose connections that was 1) not keeping the system pressurized and 2) when warmed up, allowing air into the system that was then collecting at the temp sensor so it was sitting in a pocket of air and just reading the heat transferred directly from the metal.
Get yourself an IR temp gun if you don't have one and shoot temps from around the block when it's getting "hot". At least you can then see a temp and decided to be more paranoid or not. I still have a certain level of engine temp PTSD from going through that episode. Then go through and triple check that all the hose clamps are snug. The ends of my upper and lower hardlines on the PS of the engine were rusted through where the hose clamped...that's why I couldn't keep pressure. I was able to cut about an inch off and reconnect a slightly longer hose.
2. Exhaust leak: What specifically is making you think you have an exhaust leak? It was a periodic exhaust smell with the hood open, loud engine, and bad idle for me. Turns out it was the connection of the manifold downpipe and exhaust pipe. The garbage aftermarket gasket had burned up and the nuts had loosened at the connection. 1 OE all metal gasket and 3 tightened nuts later it was done.
3. Rough idle/couldn't get idle below 1000rpm: There is a small metal tube that is molded in the heat riser under the carb. My riser was cracked where the tube goes in. A little JB weld to seal it up confirmed it was the source of my issue and shored things up until I could get a new carb plate delivered.
4. Tailpipe discharge: Mine did the same thing for a bit after I worked through my carb and fuel issues. It just stopped eventually, but not before blasting my toolbox and storage shelves when I backed into the garage the first time it did it!
5. GET A COPY OF ALL THE FSM RELATED PUBLICATIONS!!! Last I looked, the resources "library" doesn't yet have all the stuff that was available previously. We'll figure out a way to get you copies...hell, I'll put it all on a thumb dive and mail it to you if you want.
It's not the most exciting to look at, but get the emissions manual and personally check all of your vacuum line routing and connections. I ended up finding an incorrect connection that solved a hesitation I was getting when accelerating from a stop.
6. A/C: What makes you think the compressor is bad? I thought my A/C was going too, but I ended up adjusting the tension on the belt and re-charging the system and it works great now. If it really is going out, check RockAuto. I was surprised at how many OEM parts they have on there and for very reasonable prices. I know they have all the A/C parts.