I've driven this truck to work the last couple of days, have it registered and insured now. I have temporarily bypassed the heater core, but had a revelation while doing that. The inlet hose going to the heater core had been squished flat somewhere along the way, and the hose wasn't sealing well around it. I've rounded that inlet pipe back out, and now I have a theory that my leak may be at this junction rather than the heater core itself, so when I have some downtime, I'll pressurize just the core and see if it leaks, and if not, I'll put the hoses back where they go and send it.
Other accomplishments for the week include testing and replacing the thermostat, and realizing my radiator was stopped up, which was causing it to overheat. Luckily the same awesome friend the new engine came from also had a spare radiator, so that problem is solved.
I also ended up replacing the brake master cylinder and bleeding that system one more time, because the brakes would not release sometimes, and even left the truck stuck so bad a couple of times that I had to bleed pressure just to get it across the yard.
Having new hydraulics and everything working and adjusted properly have shown that this little truck has impressive brakes! It really stops well and smoothly.
I'm getting to experience why this is a great truck now, aside from just being a cheap project. They did a good job with these.
I know the photo in the work parking lot isn't as cool as photos I've posted of my other Toyota project in Moab and Colorado, but then I go back and realize there are plenty of posts before a huge trip where I was proud to post that it was finally road worthy. This is that, lol.