I assume you are referring to the air-box drains. You may have dropped part of a liner, caused by one or more liners breaking through the ports and the lower portion dropping down. On a 53, like a 92, the upper part is wet, so if the coolant is still ok, then the part above the ports is likely still intact. If it did drop part of a liner and it jammed between the rod, crank, or any part of the block, there may be block damage. If its not viable, you may try to find another engine. Old Oliver farm tractors (1900 and 1950) used the 453 and some old farm equipment wreckers may still have one that may be able to be converted to yours. The Oliver 1950t however has a Waukesha 6 cyl turbo engine and will not work