Ah, the old fiber can days with the oil spout we used to cut into the can with! Gulf Multi G 10w40, Quaker State Superblend 10w30. Those were the 2 biggest sellers at my station back in HS. http://www.jakesadvertisingcollectibles.biz/oil-gulfpride/
I hated those cardboard cans when they came out with them! I was brought up on metal oil cans and shoved the opener/spout right into them. If you shoved too hard on the cardboard cans they would collapse and you ended up with a MESS!
Oh yes, you really had to be careful. I finally invested in a really nice spout, and I swear they switched to plastic (with their own spout) within a month. Having several 1960's cars I found that the Valvoline VR-1 has high zinc levels also. I generally have used Valvoline. I was also using a ZDDP additive from Lucas with regular oil. It says for break in, but many of the Mopar guys use it all the time.
With so many recommondations and products out there what would be a decent oil to run in my '67 RW with a 390 that was completely rebuilt aapprox. 3000 miles ago? Since purchase I am putting approx. 1500 miles per year. I thought full synthetic but maybe that is not a good choice. thanks