I am considering going synthetic this year. I have a pair of souped up 540's with about 50 hours. Have used nothing but Valvoline VR40 + wix filters changed every 15 hours. Boat at LOTO so most running is in warm to hot weather.

Is Mobil 1 15W-50 the ticket for maximum protection and engine life?
Or join the Amsoil club have 20W-50 (ARO) delivered to my door?
Should staying with Valvoline VR40 be an option?

I assume stay with the WIX filters (51060R) - yes?

Thanks.

I also have a pair of 540s NA and have break-in hours (2) currently with Valvoline VR 40. I have the same questions as the previous one.

If there is no gasoline in the oil you can go 15-20 hrs..it's the gas that is the problem...if the dipstick smells free of gas...keep going...

The newest re-formulation of M-1 15W-50 EP is very nice ...no need for more unless you race.

After 20 break-in hrs on 40wt..hit it with 15W-50 M-1...

That's what the Sterling guys say they do...it's good 'nuff for me.

I have new twin 496 HOs. After the break in I plan to try V-twin.

Sounds good...keep us posted!

Hydro, Where in the scheme of things do the Penzoil products stack up ? Perhaps the conventional racing oil.

Twin 5.7 Vortec motors. Broke in with 20-50 conventional oil for 10 hrs. I have 52 hrs. with M1 15-50 and Wix filters.
So far this season they have not lost 1 drop in 32hrs, and the oil is still clean enough to see thru.
I also put M1 75-90 in the drives which I'm going to change just to check for metal on the plugs.

Penzoil conventional oils have a high parafin level which some liike and some dislike. It adds film strength but when it breaks down it forms sludge.

All in all the correct weight of Penzoil is usually good. Why racers prefer Kendall or Castrol generally I am not sure.