1999 Merc. 5.7 mpi's with 360 hours, what oil should i use ?

And on with the debate!! Valvoline 20W-50 Vr1 Conventional and I change it every 15 hrs or so.

I run ZMax. No oil, just ZMax. Carol Shelby told me I could!

For 5.7s I used the merc stuff that you buy at any mercury dealer. I didn't switch to Valvoline Racing 20w50 until I had big blocks. I would think the merc stuff will be your safe bet.

Merc, valvoline 20w50, Mobil 15w50... And on and on. Pick your favorite

Your getting ripped off. Just buy a bottle of pure linkite . Put 1.7 oz in a new motor, and it's good for life. Be sure to drain and save before overhaul to re-use....actually never mind, it will last for ever so no need to rebuild

rotella 15-40

x2. Quazzillion hrs of running these 5.7's harder than 99.99% of other owners.

Cheap + works. Next question.

Rotella 15/40 or Merc oil from the dealer.