Oil recommendations for original motor

[missioncritical]

I finally got the 70 Cuda running well and its now drivable.  So far, I can't get in touch with the original owner to see what type of oil they were running in it.  They owned it for the last 37 or so years.  Its a 383 with 80,000 original miles, so I would prefer to not change things up too much.  If I can't get in touch with the owner or they don't remember, does anyone have any ideas on what would be best/safe to run ?

Thanks

-Kevin

[1970 RT Challenger 1970]

You need something with a good dose of zddp (zinc and phosphorus) to prevent cam failure.

Search zddp here as this question comes up often.

Brad Penn, Royal Purple, Mobil1 15W50 Synthetic, Valvoline VR1 Racing, Shell Rotella T5 10W30...

[Chryco Psycho]

anything with a an SM rating has less than 1/3 of the addivities to keep the engine healthy , I have been selling a lot of the Z-Alt product