I have a 1970s 350 sbc block. Its bored and stroked to a 383 with brodix aluminum heads custom cam fully built twin turbo motor with an electric water pump and aftermarket aluminum radiator. I ran one of those flip lever radiator caps that was 16 psi. I just picked that cause it was a common psi. The overflow tank used to change level but I got a better fan and shroud setup and then I noticed the level stopped changing. Its doesnt go up when hot or down when cold and i dont know if I should be concerned or if I should try a lower psi or what. I have no coolant consumption or external leaks. The motor does not overheat and stays between 190-210. Please help !! Thanks

 

Make sure the hose to the overflow isn't pinched.

 

I have replaced that hose and made sure there is nothing ubstructing that path. I also repleced the radiator cap with a standard 16 psi cap without the lever and still made no difference.