Question : Input on Oil for '83 2.8 HO Z (LH7)

[83ste]

I am looking for oil recommendations for the above motor in a Pontiac STE. Motor is in good shape with 73K miles. As some of you probably know the newer SM/ GL-4 oils have reduced ZDDP, so this might be a problem on high performance flat tappet engines. I am not sure if these oils still meet the OHV wear spec. either. After looking around a while on the web, I can't find a definitive answer. The LH7 engine makes 135 HP at 5400 rpm, so not while super high perf., in it's day it was the state of the technology for OHV.

Shell Rotella , some high mileage oils, racing oils come up in some searches, but not all list the ZDDP content in their formulation. 1000 ppm seems to come up as the minimum ZDDP content. Another option is GM's Engine Oil Supplement.

[geoffinbc]

Shell Rotella Diesel oil will do the trick. I was told by a rep at Redline that their oil has enough ZDDP for flat tappet use and no additive is needed. You can also buy your oil of choice and trow in a bottle of zinc additive.