Posted by Clint Dixon on Sunday, June 17, 2007 at 14:58:19 :
In Reply to: Ask Clint Dixon, aka the overflow tank guru posted by Doc Dave on Sunday, June 17, 2007 at 13:25:53 :
A change took place sometime around about 1951 to 1952 as to the location where the surge tank mounted on the firewall. This was an actual change to the firewall, as the wellnuts for mounting the tank are an integral part of the firewall, whether the truck came equipped with the tank or not. My opinion is that the change probably took place early in 1951 at the time that the dash changed to the B-series gauges, but that is an educated guess.
Before this time, the tank mounted lower and closer to the fender. After this time, the tank mounted higher and closer to the engine. The change seems to have taken place so that the tank would fit on the firewall in conjunction with the Model 61 heater that was added to the Power-Wagon line at about this same time. The Model 61 replaced the old generic MoPar Model 36. Regardless of the lower or higher mounting, a radiator surge tank just does not work very well in conjunction with the model 36 heater.
I have recently seen one tank like yours with the tank halves reversed. Because the tank mounting legs are not centered, top to bottom, this would cause the tank sit even higher on the firewall. You raise a good question. Was there a clearance issue on the later trucks? I am not familiar with the heaters used after the 61, 62, 65 series. Maybe this was a deliberate change made to the tanks to clear the newer heater mounts and supply tubes.
Junior