What brand and viscosity synthetic oil should I put in my 1969 Pontiac LeMans?

It's a 350 chevy V8.All stock.


Also, should I be putting any special engine oil additives to it? I read somewhere that specific older engines need some special additives to make sure everything runs smooth.


ThanksWhat brand and viscosity synthetic oil should I put in my 1969 Pontiac LeMans?
I would stick to conventional oil, especially since it's stock. Synthetic oil is only relatively recent. Stick to what was available at the time of production since that's what it was made to run with. That's just me. Otherwise, Mobile 1 has always done good. I'm not too familiar with Chevy's so I can't honestly recommend a viscosity.What brand and viscosity synthetic oil should I put in my 1969 Pontiac LeMans?
MOBIL 1 EXTENDED OIL 10 - 30 OR 10 - 40 --------THE SPECIAL ADDITIVES ARE TO REJUVENATE THE SEALS AND KEEP THEM FROM LEAKING ----IF EVERYTHING IS GOOD IN YOUR ENGINE YOU DON'T NEED ANY ------AND GET THE EXTENDED ( 15,000 MILE ) NOT THE REGULAR MOBIL 1 ( 5,000 MILE )
any synthetic oil of 10w-40 will work fine as long as your engine doesn't use oil or leak it.