rear main cap oil groove

[rkatk]

I dropped the pan to fix a small oil leak and also the rear main cap today. When I took off the rear main cap there is no oil groove in the babbit????
- What is the best way to cut the groove?
- how far from each end of the cap do I start the groove?
- how deep is the groove?
Now I guess I need to check the other caps and maybe even drop the crank far enough to see if the upper babbit has an oil groove.
Randy