<VV> Powerglide diff. gasket

[PETER INMAN]

Ready to do the conversion from a 4 speed to a powerglide on my 65 110 Monza and plan to start tearing down this weekend for the swap. I think I have everything all lined up. I do have a question about the gasket that goes between the powerglide and the differential. Why does it have those smaller holes in the gasket that show through to the valving passages? I can determine that the larger oblong 1 inch hole is for trans fluid or air to complete circute from the pump to the converter but for the life of me cant figure out what the others do as the differential mounting surface is solid. Is there a quick easy explanation of what those holes in the gasket do? Thanks and will be glad to know why and to understand it all.
 
Pete Inman
65 Monza 110 4 speed