It's actually difficult to find oils that have enough ZDDP and redline isn't one of them. Valvoline VR1 is one of the only oils left that has any significant ammount of ZDDP and a version of Mobil 1. Ironically its the oil your mechanic should be running in his engine.
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ZDDP
Older engines with mechanical valve tappets like the ZCar L-series engines and V8s with flat tappets (not roller cams) were designed for motor oil which contains a moderate amount of zinc and phosphorus known as ZDDP (zinc diaklydithiophosphate). ZDDP is considered a miracle lubricant for engines and has been used for about 60 years in motor oil and greases worldwide. Modern engines weren't designed to need ZDDP so the modern-day automotive world doesn't even speak of it. But for vintage car and hot-rod owners the diminishing levels ZDDP in oil is a real issue because it's required to lubricate the cam lobes and prevent wear across the rocker arm surfaces.
WHY IT'S VANISHING IN OIL
While zinc is not directly harmful to the environment, if its burned due to ring blowby it ruins your catalytic converter. So over last decade the EPA has pressured the oil companies to reduce the percentage of ZDDP in their passenger car oils. This extends the life of converters...which in turn reduces total car emissions. Pressure from the construction industry allowed some diesel oils like Rotella T made by Shell to use higher levels of ZDDP which they claim is needed on heavy equipment. However, I don't like the idea of using bulldozer oil in my 7,000 rpm L28, even if it does have more zinc. Starting in 2007 construction equipment had tighter emissions standards so zinc in Rotella is likely to fade if not greatly diminished already.
Luckily there is still one company with the guts to market a higher ZDDP oil for passenger cars, in a viscosity that doesn't reduce horsepower: Valvoline. Their VR1 10W-30 racing oil is a quality SH grade oil which simply means the ZDDP hasn't been removed to qualify as a SL or SM grade. Valvoline's MSDS sheet lists it at 1.3% phosphorus/zinc, 1% sulfated ash and 2.5% calcium...which makes for a nice lube cocktail. The new SM grade oils all have about .08% ZDDP to conform to EPA standards while 2% and higher ZDDP is considered the level to use in an older motor. Valvoline states it exceeds SM levels of protection...so this is now my oil of choice, even over a synthetic. Mobil 1 is available in a high ZDDP synthetic but I find it too expensive for my tastes.
=Taken from
http://datsunzgarage.com/engine/index.htm=
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As for the filter your mechanic was probably talking about the anti-backflow valve. The Purelator has been taken apart and has been highly rated by several people who have disassembled to see what the filter really looks like. The filtering area is high as is the quality of the build including the use of a silicone seal for the valve. It's comparable to a Wix which is also commonly know as an excellent filter as well.
Oil filter comparisons
Oil Filters Revealed - MiniMopar Resources
Also check out Bob is the Oil Guy. There is a lot of science on there and you can spend literally hours reading and researching on there - it's very good.
Your mechanic is a friend of yours. Do some research and come to your own conclusion about how accurate his information is.