Oreilly's SAE 30

Quicksilver 20w-50 semi synthetic. 500EFI's

I always been using Amsoil Marine 10w40 in my motorboats

Full synthetic Mobile 1 15w-50 in Mercruiser 260 hp with 950 plus hours on original motor (206 formula) and Mobile 1 15w-50 in my 502's at 450 hrs.(32 fountain)

Mercury Racing 25W-50 Synthetic Blend in my 525EFI's...

Coconut oil. Keeps your skin nice and soft.

Valvoline VR 1 Racing 20 / 50!

Thirty years with only this in everything, low perf 330's, 454 Mags, HP500's and now in my 525 EFI's. Never a problem! If you go back and run thru some of the oil threads on here you will find that it is some pretty good stuff, lots of all the right chit.

Hey I may not be real smart, but I know some real smart people. :ernaehrung004:

If you feel a synthetic is what you're looking for, Valvoline is now making a synthetic version of the VR 1 Racing oil.

One last thing here, Racing oils are not intended to be run for long periods of time, let them do the job and change them out. They lack the cleaning additives most common oils have, they need to be changed more often.

I just started using VR1 sae 40wt. After one season, we put about 50+ hours on my motors and the oil still looks fresh! OReilly has it for around $4 a qt.

What service interval do you recommend?

mobil one v twin 20/50 awsom marine oil