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I know this is a very touchy subject around these forums. But I wanted to get some feedback on Valvoline VR1 oil and see what opinions are. I know for these aging LT-5’s, an oil with elevated phosphorous and zinc levels are helpful. I read Marc’s article and his recommends, which steer towards Amsoil with Mobil One High Mileage offering as well. The article is also 10 years old and things change. It looks like VR1 is not recommended for cats, but neither is the ZROD. Yes, ZROD and M1 HM is currently available and the old saying probably applies, if it ain’t broke….
Any thoughts on the VR1? Is it another option these days for the LT-5’s?
I know this is a very touchy subject around these forums. But I wanted to get some feedback on Valvoline VR1 oil and see what opinions are. I know for these aging LT-5’s, an oil with elevated phosphorous and zinc levels are helpful. I read Marc’s article and his recommends, which steer towards Amsoil with Mobil One High Mileage offering as well. The article is also 10 years old and things change. It looks like VR1 is not recommended for cats, but neither is the ZROD. Yes, ZROD and M1 HM is currently available and the old saying probably applies, if it ain’t broke….
Any thoughts on the VR1? Is it another option these days for the LT-5’s?
I've put nothing but Mobil One in 1990 for over 20 years now.
And my cats are still alive and well, or there's no way I'd pass the draconian SMOG tests I have to subject myself to every two years, which she has passed successfully so far.
And finally, Walmart is the best place to buy it.
They always have it and it's always on sale.
Ever since my car was with Marc in 2019, have used the Amsoil 10W-40 full synthetic AMO which has the higher zinc requirement and what the guru recommends.
The zinc and phosphourous levels of the Mobil 1 High Mileage oil in the 10 40 version appear to be more than sufficient for the LT-5's needs without introducing excessive amounts that could hinder emissions testing, even though in socialist new jersey the ZR-1 no longer has to wimper through such degrading and demeaning exercises.
I have also favored Brad Penn Green as I was a long time Kendall GT fan, but have been a Mobil 1 Synthetic user since it's inception.
Reviewing the product data sheets of various oils leads me, and just me to believe that there is very little upside to spending far more for the more exotic versions based on Mobil 1's FIFTY YEARS of performance in all kinds of severe duty applications.
Over the 30 years of ZR-1 ownership, I have experimented playing chemist by adding ZDDP, which can prove more deadly if you over-do it, as well as Royal Purple, Red Line, Amsoil, Penn Grade, etc. However, out of the 25 plus oil changes performed, at least 20 have been Mobil 1.
I usually avoid talking politics, religion, best alcohol and above all else Motor Oil, so as to maintain friendships.
But since 1976, Mobil 1 has never let me down.
This deserves personal loyalty becuase of that.
Each of you however, as friends, are most welcome to select whichever one of the above makes you happy so long as with the oil, you change it regularly; use one of the preferred filters, and then put enough miles and high RPM's on it to maintain your personal happiness!
I still have my OEM cams should the DRM ones ever re- grind themselves.
Marty
Yeah, I’m a Mobil 1 user as well, in the 04Z. I read about VR1 and the increased levels of zinc and phosphorus, so I used in the 63. Curious to see if anyone used in the ZR-1.
Yeah I put the 10w30 in the 63. I was previously using the Rotella 15w40. Engine seems to run fine with the VR1. But how do you really know? Take the engine apart? And then what, what are you looking for?
Looks like the VR1 also comes in a 20w50. That seems like it would be almost molasses.
Yeah I put the 10w30 in the 63. I was previously using the Rotella 15w40. Engine seems to run fine with the VR1. But how do you really know? Take the engine apart? And then what, what are you looking for?
Looks like the VR1 also comes in a 20w50. That seems like it would be almost molasses.
The absolute viscosity of any engine oil is relative to temperature. An engine's oil viscosity requirement is specified by the manufacturer based on the clearances in engine. An engine specifying 0W-16 has much smaller clearances than an engine specifying 20W-50. The best viscosity for an engine is also dependent on the lowest ambient temperatures it'll see as well as the highest normal operating temperatures.
From the 5W-30 GM recommends for our engines, they want the viscosity to be between 9.3 and 12.5 cSt at 100°C (212°F) as seen on the SAE J300 oil viscosity chart below.
For different oil viscosities and different ambient/ engine oil temperatures, you can go to the following website to play around: https://www.widman.biz/English/Calculators/Graph.html
The default chart has 20W50, 10W40, 5W30, and 0W20 to see how viscosity changes with engine oil temperature. You can increase the minimum temperature to 70°C (or higher) to see viscosities at the higher temps. If you're on the track and are seeing oil temps above 130°C, the 5W30 viscosity is a sufficient amount out of range that it's not providing proper lubrication. In that case, you would step up to 10W40 or maybe even 20W50. If your lowest ambient temps where you drive your ZR-1 isn't below 5°C (41°F), you could run 20W50 on the street. If you do only street driving, 0W30 is the best because the absolute viscosity is lower than any of the other xW oils and will flow quicker to all engine parts than the 20W50.
Like the guy above, I hesitate to get into oil threads because so much emotion is brought to the discussion. I like to deal in numbers which is why I posted the above. So many people have a complete misunderstanding of oil viscosity.
Thanks for the in depth response glass slipper! I know oil threads can a touchy subject, but was interested in opinions on VR1 as maybe an alternative or option for our LT5s. Maybe there is not enough experience with it yet. It’s supposed to have high levels of zinc and phosphorus, ZDDP.
I asked Marc Haibeck his opinion on VR1. He gave me permission to share his response
"The VR1 might be good. I was not able to determine for sure what the ZDDP EP additive amounts are. They are needed to protect the flat valve lifters. I recommend at least 1100 ppm /.1% phosphorus and zinc. The VR1 is a semi-synthetic so I would not use it for more than 4000 miles. Racing oil typically uses less detergent because most users change it often due to high stress. After 50k miles or so, there could be some sludge deposits."
So, the lesser amount of detergent gives me pause, but I might try this at the next oil change. I don't go more than 5K miles between oil changes.
My 1990 FSM shows 10W-30 only (-20 to +100F) for the LT5. It also says nothing about using "synthetic".
My 1991 FSM is identical to the 1990 FSM. 10W-30 only for the LT5.
My 1992 FSM shows 10W-30 "Preferred". (0 to +100F). It shows 5W-30 for <60F to >-20F. Nothing about "synthetic".
Last edited by IHBD; Apr 13, 2026 at 11:06 AM.
Reason: Posted an earlier Blackstone that didn't have the correct UAs for LT5. This one does.
OK, so I changed the oil and put in 8 quarts of Valvoline VR1 10w-30
I sent my old oil (Amsoil AMO-01 10w-40) in to Blackstone. I'll do the same and send in the Valvoline when I change again (probably won't be for a while )
If my engine blows up in the meantime, the rest of you will know not to try it
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Oil Thread
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