being a newcomer, I have been reading all the old forum posts, lots of good information there! I think I read that it is possible to install the head gasket wrong and cause over heating, is this possible? The 25 I bought is a steamer and I wont to check every thing before spending $800 on a new radiator.
Yes. You could flop the gasket on wrong. The ends of the gasket have the two slotted holes for the water jacket openings of the block, the front facing slot is smaller.
Just check that the smaller slot in the gasket is forward facing the front of the T toward the radiator.
John have you flushed the block and radiator? Does the "T" you are working on have a (gulp) water pump (if it does have one that may indicate it had a cooling problem for a while) are the fins on the radiator in good condition and tight against the tubes? There are several opinions as to the proper procedure for flushing the motor but maybe Steve Jelf will chime in with a link to his video it's always nice to see someone else do it first.
Here's the page on cooling problems. It includes links to the videos.
it has been flushed with Prestone cleaner, and the radiator was removed and flushed with a hose from top and bottom. found a lot of rusted casting slag in the radiator bottom and in the block a the water outlet. pulling the head to check the gasket is not a big job, I should be taking a look inside any way. any opinions on using something like CLR to try and open up the radiator?
If the head gasket is installed wrong, and a lot of then are, it will not cause overheating.
Don't buy a new radiator, get the old one recored.
I flush with a mixture of 25% CLR and water.
Leave it in a half hour and flush the ssip out of it.
After that you can add the new quick-flush that you can leave in for three days.
The radiator can be re-cored if the tanks and fittings are still good. It is hard to find a radiator shop which can do so correctly and if it is not done right the hood will not fit correctly.
Pulling the head is a good idea if you have no history on the engine, as you might have the infamous & likely-to-fail-at-the-wrong-moment two-piece valves. MAYBE one can check that through the spark plug hole--anyone??? 'Cause, if so, it would maybe save pulling the head to check for that.
When you pull the head, make sure that all the small water pass holes are open. They rust shut very easily and will cause the engine to overheat. Just use a small drill bit to make sure the holes in the block and the head are fully open.
Did you confirm the mixture and the timing? Overheating can be caused by running too lean on your carburetor mixture and or by not enough advance on the spark.