/6 overheating need help.

That IS pretty odd.
Usually running hot at speed is a flow problem.
What changed and when?
New radiator, electric fan, new temp gauge all at the same time?
Is the new gauge reading correctly?
Have you verified with a meat thermometer or cross referenced reading with the factory gauge?

Does the temp continue to creep up while at speed and/or does the temp get higher the faster you go? --if yes, then air or water flow problem ( or timing but since that wasn't mentioned as being changed, probably not the issue ) If the new fan shroud is blocking enough of the radiator it can cause problems. Could also be the lower hose collapsing at speed if it's old.

Does the cooling fan keep the engine cool at idle even after 15 min of idle time? if yes, the fan setup is adequate, if not you'll need more cfm.

I had the overheating at speed problem and it ended up being a low flowing radiator.
I could leave it idling in the driveway for 30+ min in 90° weather and temp would be normal.
You can check the flow of the radiator with a garden hose in the top at full open with no nozzle and the lower rad hose disconnected.
If the radiator overflows the top while the lower hose is off, the radiator isn't flowing enough.