Cooling issue, but this time it's to cold...

I've been putting some miles on my fresh 360, I took it to work this week for the first time and it was about 47 degrees out, cold, yes that's cold for me in FL. I couldn't really get any heat out of the heater unless I was at a stoplight, once I started moving over about 50mph it cooled off and I would just get cold air. I have a new mechanical temp gauge, on a 80 degree day it won't get over 150/60 degrees but drops to 135 as soon as I start driving.
I didn't think much of it since I was just breaking the motor in and I thought maybe I left out the thermostat for the break in. But today I drained the coolant and open the t-stat housing and the new stat is in there, it's a 180 degree.
Rusty, it's a 1971 Scamp with factory 318 radiator, shroud and fan clutch. Now running a 360.