Reading on site, I saw information on lack of Zinc/Phosphorus in current engine oils. I contacted Castrol to find Zinc content of their 30W. Info from Castrol:
"The actual amount of zinc and phosphorus is not published though it has been reduced in all of the oils with the exception of the 5W-50 which was specially formulated for this type of application.
Castrol EDGE with Syntec Power Technology (SPT) SAE 5W-50 has been recently reformulated to have a boosted level of ZDDP (1300 ppm) to help protect flat tappet cam engines in classic cars. This engine oil is a full synthetic, has excellent cold temperature properties, and has a high temperature viscosity (SAE 50) that is suitable for use in many classic car applications.
However,we always recommend to follow the guidelines of the original manufacturer in terms of API rating and viscosity. If 5W-50 isn't a suitable weight, we wouldn't recommend its use either."
I plan to stick to straight 30W, but may go to diesel 30W or add ZDDPlus:
http://zddplus.com/how-it-works/
http://www.amazon.com/ZDDPPlus-Engin...=zddp+additive
What do you guys use?