I did this to my Sons car this year and its working out great with Harlan Sharp rockers on Edelbrock heads. It a small block but the same idea could be used. I tapped the rocker shaft oiling hole on both heads and screwed a brass set screw in with a .060 hole in it. That way if I wanted more or less oil I could simply remove the rocker shaft and go bigger or smaller. I bought a bag a brass set screws off ebay.