I want to install a late model Thetford dump valve on my existing 1963
Overlander's black tank.
The bolt pattern is 6.5 in diagonal center to center, and 4 5/8in center to center if measured parallel.
I wonder if a modern Thetford valve would fit this pattern?
I have atached three pictures for clarification. One of the bottom of the tank, one of the bottom of the dum valve, and one of the top of the dump valve.
Andy at Inland says it might need a new flange on teh tank glassed in.
Did anyone do this recently?