You have almost the exact cooling set up I've got along w/ motor and tranny. I've got a Flex fan w/ the longest aluminum spacer I could fit. I've also go two small fans in front of the radiator on a switch to turn on when I need to. Try to push your fan as close to the radiator as possible. Get a longer spacer if you can. Also get a fan shroud if you don't have one. I have one on mine and it makes a diference. The fan doesn't do much good w/ out the shroud to direct the air towards the radiator.

I've also got the Miloden high volume pump. Mines the long pump, not the short one. I've got a Griffin radiator, and I think my t' stat is 180 but not sure. I do have a seperate tranny cooler though.

We really have almost the same exact set up . I used to have a lot of problems till I got this radiator. Other than that the shroud made a diference on mine and the t'stat. Maybe try a 180 first to see if it helps. It just may not be staying in the radiator long enough like you said. My problems were only at a stop as well.

And to really throw you off , when I was having the problems you were, I knocked the center out of the t'stat, to see what would happen. I didn't have the money for my aluminum radiator yet so I was trying everything. Anyway, it ran cooler! Makes no sense because there was hardly any restriction then, but it was a little better.

Good luck w/ it. I know how frustrating it can be.