Technical 56 Pontiac Oil?

I am wondering what oil I should be using in my 1956 Pontiac Star Chief with an original 316 in it? It has 106k miles. Thanks!

 

I use Brad Penn 20/50 w in the '57, works well for me!
You want an oil with enough zddp for an older engine.
KK

 

Thanks! Others have suggested 20/50 w for older motors. I am getting ready for an oil change and would like to put in the correct oil.

 

Been running regular old 10w30 in my 316 for years with no problems. I do add a bottle of zinc additive at each oil change though. My engine has about 54k on it and the only oil related problems I've ever had are leaks!
That being said I do plan on switching to Brad Penn and being a little more better 'bout running lead substitute in the gas! Not sure if I need to but I always run the highest octane gas I can find to prevent detonation and pinging. I'd rather spend a little more now on fuel for the sake of longevity.

 

I use 20/50W Castrol in my 55 Safari and have for the last 20 years and 180,000 plus miles with no ill effects.At $5.79/qt. it is still cheap insurance.

 

Engine has a filter so detergent oil is fine, as long as it has the zinc in it.

FWIW, you can convert it to a spin-on filter with the filter adapter off any later Pontiac V8, even a 301. Bolt on, if you can get to it under there.