I Have the same carb to blower adapter like you have. I put my carbs on there and have a 12 1/8" center to center for my inline linkage. (problem) I can not find that linkage any where that has that 12'' size linkage.
Where did you get yours from? Your's must be even longer.
Thanks Bud, Troy]
Here's a pic of my linkage. Mine is 12 11/16" c-c with only 1/16" between the bowls. Mine just consists of a flat plate to mount the throttle cable clip, a piece of steel rod with swivel Heim ends on each end for adjustment to connect the two carbs. You can make all this stuff yourself and get the Heim ends at a good hardware store. Dave