Good work Fox, Just remember where things get put after the clean up.
I also need a heater core for the 55 and tried to re solder it but to no luck. We are in our Ca. winter home and even down here things are pricy. The new core is close to $200 US bucks but like you I want a heater for the cool days. I did drive part of the last season without the core in place and it is needed. Or else the air intake passageway needs to be sealed up. But then no fresh air or a defroster for the cool mornings. I do not drive it very much or for any distance since the rear pinion seal is leaking quite a lot of oil. I need to get a larger impact wrench to remove the nut as I broke mine last summer trying to do the repair. I enjoy reading your truck adventures this last couple of years and hopefully we will finally meet up next June at the Reynolds. Work safe. Howie