The biggest issue with pushrod oiling when using bushed lifter bores is that you need to drill the bushing in the correct location so it will provide oil to your lifter during full travel.

That is easier said than done since nobody publishes the specs for this stuff. You basically have to buy a certain brand of lifter and then have the bushings drilled for that brand. And then you have to stick with the brand of lifter for the life of the motor since other lifters will have their oil hole in a different location.

I can post a picture of the spray bar if someone doesn't beat me to it. It is just a standard Indy valve cover with a tube inside that has some small holes drilled in it. A #3 AN fitting feeds the oil into the tube from outside the valve cover.