[storm9c1]

As already said, there are a few things that can be misdiagnosed as a knock. A common mistake is an exhaust leak at the manifold. Often those go away when the engine warms up. I can tell the difference in 2 seconds, but a newbie might not. It's hard to diagnose noises over the internet for people. LOL. Best bet is to take it to mechanic that you trust and get their opinion. Also, do a search on YouTube for "rod knock" and you will see procedures for dropping the oil pan and wiggling each rod with your hand. The bad one will have play where the rest will not. If that's the case, major work is ahead.

By the way, I'm digging the original white bumper. Nice.