Thanks for all the great replies guys! Wow, 1960, it is an old one! The pot will have to come appart for new gaskets and it looks like there are 2 cracked grates, I couldn't see that before.
Option #1 would have the stoker go in the back like normal and the feed pipe would go through the exaust passage in the base and out the front.
Option #2 would have the stoker go in through 1 side and the feed pipe would go out the other side.
Here are some measurments to explore option #1, Front to Back orientation;
This is about what we are look'in at.
Gonna need a longer pipe and auger for this to work.
The Losch base is about 21" wide. The S20 plate is 18" wide, no problem there.
You can see the Losch 475 boiler is on the narrow side of things.
I would put the pot about 3" lower than it is there.
If I put the stoker in through the back like this and just bolted the plate on the back of the base, 3.75" of the pot would be under the back edge of the boiler. The whole stoker would have to go about 7.5" further into the boiler to get the 3.75" ashing distance in the back of the pot.
The side to side inside dimention of the boiler is a shade under 15.5"
From the plate to the front edge of the pot is just over 20"
It looks like I can only cut about 3/4" off the side of the ring. That would only leave about 1.75" on the sides for ashing. That is realy tight!
-Don