..no-one's that keen to rush out and measure those filthy things, then..
The overall width is 5/16", the flange is 3/32" thick. The major diameter across the flange is 1 1/2", stepping down to 1 1/4" for the reduced portion that the slots in the cover ride on.
The bore is approx 1.10" (can it really be 1 & 7/64ths? -seems a ridiculous dimension to choose..), in any case, just make them to be a good push fit onto their spigots, and the reduced part to have a little clearance in the slots so that the bushes stay fixed on the countershaft head and the cover is able to slide up & over them easily..
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