Thermostat or No Thermostat?

360 .40 over, stock pistons, Eddie heads, Air Gap manifold, medium Eddie cam, headers aluminum radiator and electric fan.

I always have an overheating problem when the temps get over 85°. Not driving down the highway, but as soon as I slow down or wait at a light. The radiator is in excellent shape, no crud or anything. New 13psi cap too. I took the thermostat out last year thinking it would help but it doesn't. The electric fan is 16" high flow (2400 cfm) and goes almost top to bottom but not side to side.

Thoughts? Ideas?