ZDDP in Motor Oil, why you may need it and where to get it.

If you own a car with an engine designed prior to the mid 90's, you may need to be using a motor oil with high zinc levels. The EPA has determined that zinc and phosphorus emissions may damage catalytic converters and standard formulations of lubricating oils for gasoline engines now have reduced amounts of the additive due to the API limiting the concentration of this additive in new API SM and SN oils. Modern crankcase oils with reduced ZDDP have been cited as causing damage to, or failure of, classic/collector car flat-tappet camshafts, lifters, and/or rocker arms which undergo very high boundary layer pressures and/or shear forces at their contact faces, and in other regions such as main bearings, and piston rings and pins. Roller camshafts/followers are more commonly used to reduce camshaft lobe friction in modern engines. There are additives, such as GM EOS, and some racing oils such as Redline, PennGrade 1, and Valvoline VR-1, which are available in the retail market with the necessary amount of ZDDP for older engines, and those using increased valve spring pressures.

VR1 20w50 https://www.amazon.com/Valvoline-20W-50-VR1-Racing-Motor/dp/B00DJ4FIPQ
Brad Penn 10w30 https://www.amazon.com/gp/product/B003TPGKJ8/ref=ppx_od_dt_b_asin_title_s00?ie=UTF8&psc=1
Redline Oils https://www.redlineoil.com/
Gibbs Racing DT40 https://www.amazon.com/Joe-Gibbs-Driven-Racing-Synthetic/dp/B0095FBP5U/ref=psdc_15719391_t1_B0095FARWC
GM EOS https://www.amazon.com/Genuine-Fluid-88862587-Assembly-Lubricant/dp/B00BK7LYPW