Hummmm, just throwing this out there but same issue with two different brand heads? I assume the same brand housing/wp and thermostat? We all have our pet brands, could the hole in the thermostat not be bleeding?
No stat during test or dyno runs. No issue with Edelbrock heads, only the Trick Flow heads. We also tried a Shogun stand alone pump with the same results, so I'm reluctant to blame the water pump in this case. For all I know, there may be something hinky in the block passages that I couldn't see. No matter, I gave the customer instructions to purge the air and avoid overheating once he gets it in the car.
