eyeteeth - I know of one case where the radiator shop left a rag in the top tank when they re-cored a radiator ... same symptoms as you but that guy was able to fish the rag out when he spotted it with a mirror. (The shop lost a lot of business when word-of-mouth got out, although they already had an iffy reputation before that.) I prefer new radiators as I haven't had good luck with re-cores. New ones can be difficult to find. Right now, the only person I'd trust to do a re-core is CJ at Fairbanks Radiator.
z89101 (Mike) - gray water is fairly easy to deal with, although you might want to check state regulations regarding disposal. Restaurant supply stores often have relatively inexpensive 5 gallon plastic jugs that might work for you. (Black water tanks have to meet more strict regulations.)
I'm 99.9% sure your transmission is an A727 TorqueFlite/LoadFlite ... probably one of the best automatics ever made ... ****-near bullet-proof as long as you change the fluid and filter once a year and keep the fluid topped off. I've put various ones through some extreme uses and the only time I've had to rebuild one was due to the previous owner running it dry. (I've seen one A727 in a 5-ton truck that was original and continued through four engine rebuilds without having to be rebuilt itself.)
The big block A727 has a different case then the small block version. Internal components are the same, with slight variations based on the vehicle they're going into. The big block A727s are getting to be fairly rare, mostly because a lot of them (esoecially from motorhomes) were taken to be used in race- and drag-cars. I mostly work in small block Mopars but I'm tempted to find one or two spares just in case I run across a need for one. (My daughter has one of the very rare early-60s pushbutton versions ... case is different but internals are mostly the same as yours.)
One change I do like to make on A727s is an aftermarket extra-capacity oil pan. (Oil pan and filter is the same for big and small block versions.)
Your rear axle is probably a Dana/Spicer 70. On the right (passenger-side) tube is a build number stamped into the tube which can be used to determine exactly which version you have. The only way to definitely know your ratio is to count the driveshaft/wheel revolutions or the teeth on the ring and pinion gears. (I don't trust any tags -- or even the build number -- because someone may have re-geared it.
