grade of moter oil

[Bayon-M/C]

have a 460 and i am thinking of what type and grade of oil to use in my crank case.i have very little history about my boat, it seems to run out very nice.dont want to wreck anything that may be a little worn.

[gqchris]

I use VR1 50 Weight in my 454 with mild build. Has worked out great for me.
Chris

[IMPATIENT 1]

i break in with rotella t, and after break in i run castrol straight 30w wether its a bbc or bbf

[ck7684]

General rule of thumb is to run the lightest weight oil you can to maintain proper oil pressure. This puts the least strain on the oil pump and keeps oil flowing well...

[Bayon-M/C]

so it would be best to use a signal grade than a muli-grade

[soulboater#1]

I run Valvoline racing straight 50w in my 460(.30 over) It works good.

[Devilman]

Valvoline 10W40

[uLtRADeNniS]

I run Royal Purple 50w in a 554ci

[TahitiTiger]

I run Quakerstate 20-50w in the 455. No issues yet. :D I have always run 20-50 in my older vehicles, 67 390 Mustand, 69 300 I6 F350, etc.

[Boostedballs]

Just as long as you can stay away from cheap oils that have not had the paraffin removed completely. These are: Pennzoil, Quakerstate, and Havoline. (and most off-brand oils) Those oils suck! They work fine as long as you change your oil every time you change your socks! They will however, leave a nice thick sludge in your lifter valley and oil pan so when something comes loose, it won't find it's way back into the lubrication system!
Stick with good oils like: Castrol, Valvoline, Mobil 1, and any quality synthetic oil.
Like said earlier: choose oil based on oil pressure at operating temp.
80psi with a hot engine is bad news; so is 5psi. Thick oil creates heat and kills horsepower, but if you have a ton of hours on your engine and you have low oil pressure, it may be time to step it up to a thicker oil.