Cujet
HDEO Bike and race oils tend to contain more "ZDDP" than the "critical" SL level
The reduced ZDDP is an issue for flat tappets crowd
Delta cams
Comp Cams
EPWI engine part supplier
Amsoil (but see tech bulletin)
Redline oils
Castrol oils
http://www.castrol.com/castrol/productdetail.do?categoryId=9006583&contentId=7013363
Pennzoil
Spectro oils
American Engine Rebuilder's Association
General Motors
Moss Motors
Hot Rod Magazine
Power and Performance News
Hughes Engines
Motorcycle Cruiser
Motorcyclist
Royal Purple
Penrite
Joe Gibbs
http://www.joegibbsracingoil.com/datasheets/81106.php
http://www.lnengineering.com/oil.html
http://www.amsoil.com/dealer/techservicesbulletin/TSB_flat_tappet_and_camshaft_lube.pdf
Fuchs Titan GT1 Zinc free (flat tappets should not be an issue)
Typical replies from oil companies
Pennzoil has marketed, for a number of years, a "Pennzoil Racing Motor Oil" that would be suitable to use in older vehicles or high performance engines that incorporate high lift cams with high tension valve springs. The Pennzoil Racing Motor Oil is available in the SAE 25W-50, 50, and 60 weight. The product part number is 3623, 3589, and 3599 respectively. Given the part number, any retail outlet that carries Pennzoil products, can obtain this oil. This formulation contains nearly three times as much zinc as most commercially available API "SM" motor oils in the market. I would recommend using this formulation, for truly high performance engines, over the heavy -duty diesel engine oils because this oil has approximately 50% more zinc than most API "CI-4" quality diesel engine oils.
Best Regards,
Technical Service
The Red Line oils continue to offer very good
protection, we will not reduce those critical levels.
Thank you for contacting Castrol North America.
The GTX Line has a zinc level of 0.075%.
As indicated on our product packaging, the current engine oil category API SM/ILSAC GF-4 is fully backwards compatible or ‘back serviceable’ and has been extensively tested. Valve train issues are not anticipated with the use of modern engine oil in older cars of OEM stock configuration. In fact, current SM/GF-4 engine oils are subjected to testing that is far more intensive than engine oils of previous API/ILSAC categories.
To clarify, in general, ZDDP levels have been reduced a small amount in the current category engine oils (API SM/ILSAC GF-4) in compliance with industry regulations that set maximum levels of Sulphur and Phosphorus, but are still at levels that provide ample engine protection.
BP
Anyhow, engines such as yours that use flat tappets could be sensitive to reduced levels of Phosphorous in oil formulations, it appears that 0.1% is about the cut off point, so oils for flat tappets should contain >.1%.
Phos has been steadily going down as the amount of ZDDP has been reduced to ensure compatibility with exhaust after treatment
From our range the following are higher than 0.1%
Castrol GTX Diesel 15w40 (CI4,CH4,CG4,CF4,CF,SL)
Castrol GTX High Mileage 20W-50 (SL,SM)
Castrol GTX 20W-50 (SL,SM)
Castrol HD 30 (SL,SM)
Castrol HD 40 (SL,SM)
Castrol Syntec Blend Truck 15w40 (CI4,CH4,CG4,CF4,CF,SL)(Semi-synthetic)
Castrol Tection Extra 15w40 (CI4Plus, CI4,CH4,CG4,CF4,SL)
Castrol Hypuron S 15w40 (CI4Plus,CH4,CG4,SL)(Semi-synthetic)
Castrol Syntec 5W-40 (SL,CF)(Synthetic)
Castrol GO! 10W-40 Motorcycle Oil (SG)
Castrol GO! 20W-50 Motorcycle Oil (SG)
Castrol Grand Prix 4-Stroke Motorcycle Oil 10W-40 (SG)
Castrol Grand Prix 4-Stroke Motorcycle Oil 20W-50 (SG)
Castrol TWS Motorsport 10W-60 (SJ)(Synthetic)
Good answer from TeeDub and Amsoil tech bulletin