I have too much experience with this LOL
Do you have a fan shroud on the motor side?
Have you verified that your temp gauge is accurate?
I have struggled with this here in AZ and here is some leanings.
Anybody that says a shroud is not needed does not need it
My 79 with a LS7 uses two electric fans and a custom shroud.
My 69 with a 468 BB has two electric fans and a shroud.
The shroud also has small square rubber flaps that open at high speed to allow air to flow thru the shroud and at low speed they close so that the fans can pull air around the whole radiator. This allows for it to cool off at highway speeds and provides better cooling at stop signs.
Other things to pay attention to:
Bigger 2 or 3 core Alum radiators are more efficient than the 4 core brass.
I know you said your using a 185 but for others Is your thermostat A 160 deg thermostat that is open in the summer all the time!
Try a 185 or 195 to allow it to close and provide more cooling to to the water.
Get a high flow thermostat so it does not restrict the flow when it opens.
Use Water Wetter with WATER not antifreeze .... water transfers heat better "It really works".
Check your radiator level and use an overflow that works - make sure your cap is working get it pressure tested and pressure test your radiator.
Be sure your timing is not too advanced or causing detonation -
With an automatic trans - use an external to the radiator trans cooler so your not heating up the radiator water as much. Some people buy pass the radiator all together and get one with a small fan on it.
Hope this is helpful -