Big BB temperature fluctuation

[KobraKarl]

Blue sky again today so I went for a spin and noticed again that my engine temp is very unstable.

I have been overlooking this due to more pressing mechanical needs, but I am wondering whats the deal ,and is this just part of the bastard cooling systym of the cobra BB ?

I understand that in heavy traffic or hot weather of course it is going to run hottish, but on a 60 deg. day at 40 or 50 mph the temp wont come up over 150 deg. unless Im stopped a while and then it will fairly quickly heat toward 190 to 200 if I dont hit the fan switch.so back and forth goes the temp all over town.

I'm concerned that this constant temp cycleing may be a little hard on the engine, or is this the way it is for you too? it has a new 180 deg, stat.

thanks Karl