What kind of oil?
if you are still on the stock block use 5w30 synthetic, but anyone using a crate motor with aftermarket bearings, the weight of oil will depend on the bearing clearances. i use valvoline vr1 race oil 20w50 for mine, simply because thicker oil will prevent you from spinning the infamous rod bearing
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Verdad Gallardo oil choice is going to be dependent on too many factors. We can really only recommend oils. and I will tell you there are lot better oils to use on MR LT1 than stupid M1 5w30 and 10w30.. 
Valvoline 20w50 VR1 stuff is a good racing oil, but not very good for something that gets regular oil changes.
Valvoline 20w50 VR1 stuff is a good racing oil, but not very good for something that gets regular oil changes. 
As far as the quality of the base stocks used in synthetic oils, the best out there are Amsoil, Royal Purple, Redline, and Mobil 1, not necessarily in that order. For a high performance application or high stress/high sheer, the synthetics will 9 times out of 10 be better than any conventional...racing oil or otherwise.
As to what weight, that is dependent on climate and also clearances as said earlier. Amsoil has invested quite a bit of money in their own research and also 3rd party research and has published some data showing their oil to be better than some of the other leading synthetics. Do an internet search and you can see some of those results. I currently have redline in my pan, but I think I may give the amsoil a try for a while. I've used both Mobil 1 and royal purple in my stock bottom end before my recent rebuild with good results also. I don't think you can go wrong with any of the above listed if you are running the right weight. Mobil 1 is the most convenient and readily available as well as cheapest of the 4 if that factors into your decision (it doesn't in mine).
As to what weight, that is dependent on climate and also clearances as said earlier. Amsoil has invested quite a bit of money in their own research and also 3rd party research and has published some data showing their oil to be better than some of the other leading synthetics. Do an internet search and you can see some of those results. I currently have redline in my pan, but I think I may give the amsoil a try for a while. I've used both Mobil 1 and royal purple in my stock bottom end before my recent rebuild with good results also. I don't think you can go wrong with any of the above listed if you are running the right weight. Mobil 1 is the most convenient and readily available as well as cheapest of the 4 if that factors into your decision (it doesn't in mine).
Originally Posted by Turbo_6
As far as the quality of the base stocks used in synthetic oils, the best out there are Amsoil, Royal Purple, Redline, and Mobil 1, not necessarily in that order. For a high performance application or high stress/high sheer, the synthetics will 9 times out of 10 be better than any conventional...racing oil or otherwise.
umm you forgot mr German Made Castrol Syntec 0w30...
Originally Posted by burnzilla
As soon as I got over 80K, I switched to Mobil 1 10W30.
I think 5W30 is a little lean for LT1's, but im up here in NY.
I think 5W30 is a little lean for LT1's, but im up here in NY.
both are considered "lean" compard to other 30 weight oils. Hence the reason why Mobil 1 5/10w 30 oils get called "thin" Remember the 30 weight is a range of measurement, not an exact thing
Originally Posted by buffman
both are considered "lean" compard to other 30 weight oils. Hence the reason why Mobil 1 5/10w 30 oils get called "thin" Remember the 30 weight is a range of measurement, not an exact thing
SAE 10W30 and Synthetic 10W30 are exactly the same weight, dexterity, etc... and must pass all the same tests. One is not "thicker", or "thinner" then the other.
There are chemical properties in the synthetic that makes it last longer and provide more slippage/lubrication... thats the difference.
I used to think there was more of a difference until Chip Foose proved me wrong.
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I can't imagine running 0w30. Starts as 30, and when warm is 0w.... I'd fear leaks...
I haven't changed mine yet since I just got the car. I'll probably run 5w30 since it's winter, but 10w30 for the summer. My TPI Bird I just ran 10w30 year round.
I haven't changed mine yet since I just got the car. I'll probably run 5w30 since it's winter, but 10w30 for the summer. My TPI Bird I just ran 10w30 year round.