Lucky,
The reason not to go with a bigger main is it is already too rich at WOT.
As far as I remember, the shims did fit into the recess.
Thanks Brewsky for that info.
Ok ...I see what you meant about WOT issue.
So if you took off the shim and keep the #42 idle jet maybe that would be the way to fatten up the midrange?
Sure wish you knew about that washer fitting down in that pocket because that is a .012 difference. Well .012 from .019 is + .007 thousandths difference.
Let us know if you rework it . Thanks.
I know it is a lot of work.