what is the towing capacity for a 1989 chevy 1500 series with a 350 ci. engine?
It should be listed in the owner’s manual.
There is much more to safe, enjoyable towing than just that number listed in the owners manual.
As a sample a neighbor used a truck with a 10 K tow capacity and lost control of the vehicle and trailer while towing less than 5K lbs. Fortunate to “survive” and learned quickly that a poorly loaded trailer and an empty truck bed was an accident waiting to happen. Some experienced towers can handle at tow limit. Otherwise, as “oldschool” says, there’s more to towing than just weight/tow limits.
I don’t know what the official manufacturer-determined towing capacity is, but in my opinion, it depends on the condition of the truck. If it makes strange noises when you go over a bump or turn the steering wheel, has rust on the body, and has old worn out shock absorbers, I would limit it to 2,000 pounds. If you maintain it well, and all of the suspension components are in great shape, I would probably limit it to 4,000 pounds for the sake of preserving an engine and transmission that old. Either way, you should find the owner’s manual and make sure you follow all of its restrictions and recommendations on towing.