VR1 20/50 for years with 2 changes per season.

 

Personally... I really like the Joe Gibbs 15/50 XP4... (BR30 for break-in) really good stuff, about the same price range as the Valvoline (when not on sale), and what I use in all the engines we break-in and dyno... the stuff has crazy amount of additives and what sold me was the fact that even after running the holy living piss out of my gullwing for over 130 miles in a day ar 4k rpm... the oil pressure was still great, oil temp stable, and when I drained it, it still was in good shape and still a bitch to clean off my hands.

BUT...


I've had good luck with:

Brad Penn (though not super conveniant to obtain, I like it as much as the Joe Gibbs as far as conventional oils go and put it in as a tie for #1)

Lucas Racing (Pretty good stuff, takes a beating pretty good and maintains oil pressure. The 10-30 synthetic is a bit spendy, but on the dyno, back-to-back pulls was worth 12hp over the Valvoline and held up much better)
 
Valvoline VR1 20/50 (fairly inexpensive, easy to get, will work fine, but I still like to use additive with it, especially during cam break-in)


My favorite line of all time concerning oil is: "Well... for cam break-in, I used the cheapest oil I could find since I was gonna change it right away... that is what my engine builder told me to do."... said NO engine builder EVER!

Lucas Racing (Pretty good stuff, takes a beating pretty good and maintains oil pressure. The 10-30 synthetic is a bit spendy, but on the dyno, back-to-back pulls was worth 12hp over the Valvoline and held up much better)

Thank you again for the reply.

I have read some literature pertaining to lubricating plain bearings in machinery.  I have not yet been able to fully digest the material, nor have I been able to dedicate sufficient time to the topic.

If I am understanding it correctly, a higher RPM requires or dictates a lighter weight oil.  Any thoughts here?

Do you clearance your engines differently based on intended oil viscosity, meaning one specific build will use only 10/30 vs. another that will use only 15(20)/50?

Thanks again,

Joe

I'll play.

In the early 90's, On the marathon rig, which was a naturally aspirated 496 with a 12 quart oil capacity and oil heater/cooler (oil cooled with warm water) we used the old Valvoline Racing 50. The reasoning was simply that it netted the most desirable oil pressure readings (65 psi at 5,500 rpm) and it was part of a sponsorship and was provided gratis.  (Major decision paradigm there lol).

I don't believe in multi viscosity pulls with large deltas. First off, I've never run my crap in freezing temps,  second, I feel the polymers take a little something away from the oil.
I have been using Amsoil in literally everything for about 20 years now, I still try to keep close on the viscosity for the known weather stuff,  but when it coves to the cars,  I run the recomended weights.

I know what my clearances always were in the race stuff and felt comfortable enough making the decisions I did,  but to be totally honest, never had the tech to know for exactly sure. I can tell you, we never had ANY oil related failures.  Rocks the size of small cars were always our downfall. Lol

GT