I have a 67 326 no AC, this engine has been completely rebuilt 30 over. The problem is heat,
she loves to hang around the 210 mark and when you come to a red light, she will go even higher if you let, and then she starts to Vapor Lock.

I have done the following, please see if there is something I may have missed.

New themastat 160 (2 Times)
Smaller Pully on the water pump.
2 new radiators (3 Core)
Racing Antifreeze to keep motor 10 15 deg cooler.
Electric fan only, 16 inch

all parts on this engine are all brand new, today after putting another new radiator on it, she held 180 for about 10 minutes ideling, when I took her on the road she climbed to 210, I turned on the heat to help disipate and anti freeze started coming out of the heater core inside the car.

What am I missing, I live in SC and it was not that hot here today, anybody with any sugestions, please email me at lancehendrix@charter.net

Thanks