all removing the stat can do is slow the time it takes to get hot or keep it running too cold for best performance and longevity - I'd also want to know what a good thermometer says the temp is in comparison to what the gauge reads, gauges aren't the best/primary indicator of overheating unless you've first "calibrated" them ... also a good warmed up 350 is meant to have a 14# or more cap, 7# doesn't take the pressure 190-200* generates, did you put a higher pressure cap on the new rad?
Bill
