[79TRANSW72]

Looking for oil recommendations for a 78 Trans Am Pontiac 400 W72
Viscosity, Brand, synthetic or not.

[TAKerry]

You will most likely get 10 different answers.

A high zinc content is preferred. The only oil I now use in everything is Shell rotella 15w40. Its a diesel oil but high in zinc. I use in on advice from the fellow that built my motors. Its all he uses in everything.

[Jay S]

I would prefer Driven HR5 10w40 in that.

Most Diesel oil is formulated for EGRs with anti soot additive packages on modern diesels now. Not a great fit for old gas engines like it use to be.

[Pershing]

Yes, you will get plenty of recommendations. So I will just tell you what I use in my 1957 to 1972 cars: Valvoline VR-1 conventional in either 10w-30 or 20w-50. I only drive them in 40+ degree temperatures so the winter rating is not a concern. The oil has over 1000 ppm zinc and phosphorus, but so do others like Mobil 1 15w-50 and some of the Mobil 1 Euro oils, same with Brad Penn and Driven. You probably won't go wrong with any of the oils recommended here.

[78w72]

Originally Posted by 79TRANSW72

Looking for oil recommendations for a 78 Trans Am Pontiac 400 W72
Viscosity, Brand, synthetic or not.

If this is a stock engine/cam you do NOT need a special race oil like VR1 or 20/50... read the owners manual, it states what weight oil to use, usually 10/30 or 10/40.

The small stock cam is fully broken in so it does not need specialty high zinc oil or zinc additives... all modern oils have plenty of zinc for these small cams, but modern oils also have other anti wear additives that provide all the protection a stock or small cam'd engine needs. Most prefer conventional oil over synthetic for older flat tappet cam engines.

Modern oils have far better base stock oils along with 900-1000 advanced zddp (zinc) that doesnt require as high of level and other additives that protect stock or mild bigger than stock cams. Pick a brand you like & save some money over race oils that are simply not needed for stock engines!

Also, rotella T oil is not what it used to be, its actually lower in zinc than most other brands of diesel oil, last I saw on oil analysis tests, delo 400 was highest along with fords motorcraft and even walmart supertech 15/40 had higher zinc that rotella t.

[TAKerry]

Shell Rotella has approx 1150ppm of zinc.

[Jay S]

They have brought the SN rating back for Rotella T4 now (older rating for gasoline engines). It was missing for a lot of years when they were messing with the chemistry for soot, it only had Diesel ratings. The chemistry has changed on it a couple times, this is the third time in the las 20 years, this last time I think was for the better. I have it in one one of my old cars. Convenient when I have 5 gallon buckets of it around for my Diesel engines.

[Formula403]

So, did you simply just get what was on special anyway?