the original trucks used nondetergent oil in the 50's. seals were made from materials that were compatible with nondetergent. Today, you have a hard time finding nondetergent oil. What do you use now? How often do you change it?
There's a heating and industrial oil company near me that supplies non-detergent oil in 5 gal. pails. It's reasonably priced and the pails make great containers for carrying oil to the recycler. I believe I used 20 weight non-detergent for the first few hundred miles after I rebuilt the engine. Of course I used modern gaskets, etc so I don't anticipate a problem with the 10W 30 that I use now. I usually feel that I need to change it more for time passed than for miles since I don't currently drive the truck that much. I'm sure there are multitudes of opinions on this subject throughout the internet. good luck
Oboy ! An OIL THREAD ! FLAME ON You needn't worry about adding modern oils to your old clattery 216 engine ~ they'll love it , even synthetics . That B.S. about seals is just that ~ BS . Buy the very best oil you can afford and change it often , always when HOT and you'll be fine , really . Do not , EVER put non-detergent oils in anything but a recycle bin where they belong , certainly not any engine .
I don't think that the type of oil is the issue here. I think the underlying issue is simply this: put whatever oil you like ( mine starts with a "P" and ends with a "Zoil"). I've used that oil forever, HD30 in the summer and 20W in the winter on all of the old 216's i've had. My point is: it doesn't matter what you use as long as you check your oil level, change it regularly and maintain proper tune up on these old 'bolts. Nothing beats an old stovebolt as far as reliability as long as you keep them maintained! My dad bought my '50 in '83 and run it every day hauling trash, gravel, hay, etc until '98 with nothing but regular oil changes and occassional points, plugs and condensers. In the immortal words of Forrest Gump: "That's all i have to say about that!"