Another overheating situation 63 Slant six

So time for an update.
A perfect example of Occam's razor and the principle of parsimony, I took the radiator off and was going to go get it tanked at the radiator shop 20 miles away, but having read so many good suggestions, I decided to run the garden hose through the radiator. Turned it upside down and full blast, the water ran through without backing up at all. Thought I'd try my old radiator and water just trickled through. Nuff said.
I also took the suggestion of removing the brackets from the old radiator and putting them on the replacement. Not a totally perfect fit but none then less, I got them on.
Put the radiator in and drove the car and was able to go much further for longer this time just cruising and temp was about 160. I got on a back road and punched it really hard and fast for a little bit and watched the temp climb to about 210-215. I got home fan came on and cooled down pretty quickly.
I mounted the original 4 blade fan, yeah I know, get a flex blade, and had adequate clearance from the radiator.
Took her for another drive and the temp was down below 160.
Tomorrow or Tuesday it'll be a new thermostat and work on through the other issues.
Thanks for all the help and suggestions yall.
John