Oil Recommendation for 71 Corvette

[bandz7]

My father has a 71 350/270 Corvette. The engine was rebuilt about 2 years ago. He doesn't drive it much. I am considering Rotella T6 5W-40 with a Wix Filter for the car. Does this oil have the best add-pack for a 350? Mobil 1 15W-50 was high on the list, but it's getting too tough to find. Right now there is Valvoline 20w50 conventional in the car. Any other recommendations or will the T6 be the best choice?

 

[charbaby]

IMHO Only!
We used anything 10W40 in most engines back then even in a stock Corvette. Your decision on Rotella T-6 5W40 sounds perfect and the WIX filter is an excellent choice. The 40 wgt in MD summers is fine as everythime I visit MD, it in the low 100's deg F.

 

[Radman]

Rotella T-6 would be my top choice for oil. As far as filters go, Wix, Pure 1 would be fine too.

 

[addyguy]

T-6 all the way.

 

[mechtech2]

Forget the 20-50.
Enjoy the HDEO 5-40.

 

[VWguy]

That is a very nice car. I would suggest if you know who rebuilt the engine, ask what cam/lifters and valve spring rates are used. This would dictate brand as some builders and cam mfg's spec certain oils to protect the previously mentioned parts. Lots of stories of engine damage because warnings were not adhered to. Just google "pitted lifters" or "flat cams" and see how widespread it was and still maybe. Choose your viscosity based on oil pressure on a fully warmed up engine (10psi per 1000rpm is a general rule). I believe the Rotella T Synthetic 5w40 is a great oil at a bargain price. The additive package is probably ok if the engine was built conservative.

 

[NHHEMI]

I would be running something like Bradd Penn or Royal Purple XPR racing oil in that with the needed ZDDP. I would avoid modern SM/SN oils unless a roller lifter setup was added.

 

[UNC017]

T6 would be a great choice. So would Mobil 1 0w40, although it probably has a little less ZDDP (but still a healthy dose). I've run both T6 and Mobil 1 0w40 in both my 60s big-blocks. Remember its not the SM/SN rating that puts the sub-800 PPM limit on ZDDP, its either the ACEA or ILSAC rating (I honestly forget which). I also think it doesn't apply for 40-wt and heavier oils. That's why SM/SN rated Mobil 1 0w40 and RT6 both still have around 1000 PPM, which is plenty for an engine that's already broken in. What I wouldn't do is run Pennzoil Platinum 5w30, Mobil 1 0w30, or any other Xw30 oil aimed at modern engines. Those oils are definitely limited to <800 PPM.

 

[CATERHAM]

Go with a 30wt HDEO or any modern 5w30 and buy a bottle of Red Line Break-In Additive to bump up the phosphorus level.
One bottle is good for about 5 oil changes.

 

[bandz7]

Should I also look any additives like the Caterham mentioned? Do I need to add some Moly for this 350? I started looking into the T6 because of the nice zinc, phos and magnesium levels, but in the VOA posted recently on T6 there doesn't seem like much Moly.

MOS2 is hot right now on this forum, is there a VOA on it?

 

[A_Harman]

No need to add moly if you supplement a SM or SN 5w30 with Redline oil additive. You can bring the Phos content up to ~1400ppm with a few ounces of the RL. That would be equivalent to what SE and SF oils were back in the day.

 

[tflessner]

Originally Posted By: NHHEMI
I would be running something like Bradd Penn or Royal Purple XPR racing oil in that with the needed ZDDP. I would avoid modern SM/SN oils unless a roller lifter setup was added.


Amsoil also has a 10w-40 with added zinc for older flat tappet cams.

Just another option.

 

[steveh]

Rotella T5 10w30

 

[jorton]

Originally Posted By: VWguy
Just google "pitted lifters" or "flat cams" and see how widespread it was and still maybe.


I was going to suggest any 10w-40 for a gasoline ohv engine that's rebuilt with oem, not racing parts. But I haven't researched Corvette engine engine damage.