About the length (circumference) I just guessed a length.. if your center to center distance is 8 5/8 then it's a 203786A indeed and you'd want a number ending in 348
since it outside circumference is 34.83"
but as I said the length was just an assumption;
important is the width and angle
I thought the belt you have installed in the pictures reads 25-28333
and that's too narrow and has the wrong angle (and is obiously too short

)
'sid