This is looking more like it:
https://www.millertire.com/products/tire-supplies/tire-paint/1-quart-black-tire-paint/
Gets great reviews. It is slightly concerning that it is a private label "Miller Tire" brand. If it were that good, you'd think a major car product company would have it in...
I was talking late 70's early 80's. I'll check out your suggestions thanks UncleDavy. Everything I have used since is more like a dressing and varies from slightly to very greasy. The product I remember was much more like a paint. Very clean and dry and durable.
Does anyone know of a product like this? I used it as a kid. It was like a paint available in gloss and matt. Water-based. Apply with a paint brush. Let it dry. Formed a nice black skin on the tire that you could wash and it lasted a long time (never cracked or peeled that I remember)...