The Stovebolt Site Forums The Shop Area Engine Shop Again, what's best MOTOR OIL/ZDDP

Time to change oil in 261, solid lifter motor. Also ZDDP, Valvolene racing oil contains ZDDP but pricey!

Check the chemical makeup in STP, it should have what you need to protect your motor, and it is available
everywhere.

I sometimes add a 1/2 quart of Shell Rotella when changing oil in my 235 (1962). Those solid lifters seem to be fine with it. Also, Hemmings sells ZDDP laced motor oil although I have never used it.

I have had excellent luck with Brad Penn, now called Penn grade 1.

Because STP viscosity is so much heavier than motor oil, I only add it to a warm, running engine slowly so that it's dispersed into the pan evenly.

Valvoline VR-1 is what I've used. It is less expensive than others, available everywhere and you can still get it in straight 30 weight. In the 235/261 you don't have the same things working against you as you will in a racing engine, you know...

Penn Grade, VR-1, Driven, all very good oils. Rotella, also a good choice. STP, not so much, read up on it and you won't ever use again. Race engine need extra protection due to heavy valve springs, yours doesn't. Go to your local GM dealer and see if they have EOS, an over the counter oil supplement, add a 1/2 can to any oil you like. Lucas sells a similar product that works well. Your valve spring fully compressed are still likely less pressure then some racing springs uncompressed.
Quality products don't come cheap!

I use vr1 and like it but someone on here turned me on to 15w40 diesel oil which I already use in my tow truck. Its already in my 63 305e and will be in my 261 next go around. Tractor Supply has it cheap online in 10qt jugs. High zinc to boot.

Yep! Rotella 15w40. When bought a new 2000 F-250 with the 7.3 diesel. First oil change I went and got a 55 gallon drum of it from Sam's club.
Use it in everything except the air compressor and the newer cars that require synthetic.
I believe I am on the third drum in almost 21 years.

The old 7.3 is still pulling good!, But rust, is another topic.
Don

Joe H That EOS was good assembly lube but I dont think GM has it anymore,friends used to use STP but it is such a dirt catcher and hard to get off of stuff. Have learned hhow to buy zddp at the FLAPS one of my oldies uses some oil so just add 2 oz. when Iput in a quart so far all lobes are on duty !!