The head is stock and has not been drilled for the head oiler. The return oil through the valve cover is not going to work very well, plus it is not legal.
You need to upgrade the cooling system to a better, legal system. There are many options on the market, so ask questions and pick the one that you feel is the best.
I offer one set-up, VMS, HSR, Buckeye Legends and dozens of others offer cooling kits. Talk to each one independently and make you decision based on the info you gather.
Randy - RPM