Back in the day it was also popular to paint the lifter valley with multible coats of gloss paint to speed oil drainback. I never did it for fear of the paint flaking off and stopping up the oil pump but a lot of guys did.
That paint is still available - it's "Glyptal"; GE used it for many years in industrial electric motors - oil doesn't bother it.
Glyptal is NOT a paint, it is a Air Dried (Cured) insulating varnish used in electrical motor and armatures.
The current formulation is found here:http://www.sprayon.com/products/red_insulating_varnish
It resists solvents, fuels and heat. Excellent hot rod product for the oil rain back surfaces in any motor, Esp those little 302's ,,,,,,,,,,,,