Has it always done this or is it something new? If it did not used to be like this, have you done anything different or changed anything that might have caused the problem.
For example if you just rebuilt the engine or something like that, you could have something together wrong. I honestly don't know if it applies to Chevy smallblocks but I know it is possible to put the headgaskets on backwards on the 3.0 Toyota V6 and if you do, it will block some of the coolant passage holes and the motor will run too hot. Is there any possiblity that you have an issue of that nature?
