Ok, so I have rebuilt and installed my new engine, its pretty much run in now too.
Still gets hot on 30 + days, although the temp only increases from the 1st line (normally sits here) to halfway. Gets hot when sitting at over 3750 rpm.
Having the heater tap open helps, didn't replace water pump or anything cooling related (has new thermostat though).
Coolant doesn't get blown out the radiator cap like it used to, so thats a plus haha.
So new rad cap may help, and pump. Seems to me like an inherent issue with K engines, I don't really like how the coolant is supposed to flow between head and block, the headgasket doesnt allow for efficient flow (just my opinion).