The radiator was just a cheapo oem style radiator. Since I first posted this I overheated pretty bad driving up a mountain pass. Was holding steady at about 215 - 220 then my gauge light flashed and it shot up to 260. I pulled over and it cooled down almost instantly and drove the rest of the way up at about 215-220 again. I then replaced the cap and tonight I am going to replace the thermostat with a stant hd with self drilled hole. I am starting to think I should just order a 3 row radiator to replace the ebay one I put in. But first I will try the thermostat then a water pump. I want all the stuff new under there anyway.
I'm with the others in regard to radiator.
Single row will cool quickly when the driving load is reduced ... but has difficulty providing sufficient cooling underload - in certain conditions ....
Once the engine temp exceeds the ability of the little radiator to cool ... its all over ... and confirmed by the temp spike - similar to what happens, when the radiator cap is faulty.
Your post comments above are just like reading the basic overheating causes in the FSM.
Hills, high weather temps, high speeds ......
30/70 or less antifreeze mix and a 180/185/190 thermostat might keep you out of trouble for a bit ... Its what I used for a long time ... but a better radiator is
the fix ...
Be cautious of 3row radiators ... as they can have airflow issues ... Ive found a quality 2row is more than adequate ... altho most seem content with the CSF 3row performance.
Not all radiators are built the same ... internal flow tubes diameters vary as does fin style and spacing. The tubes in a good radiator can even be "dimpled" to tumble the liquid for improved heat shedding.
Aluminium ones are high maintenance but have a good service life if well built ... whereas copper / brass ones cool slightly better and are easier to fix in the event of a leak.