gunk under intake manifold

Since I bought the car it has always started, not sure how healthy it runs lol but that’s why I’m working on it. I had an issue with over heating and that lead me to water pump, then thermostat housing and found the rust inside manifold so I kept digging to see what else I can uncover. Not to happy about the gunk and stuff but it is an old engine. I’ll clean what I can with tips from you guys, hopefully get it running and not overheating and when money allows get it professionally rebuilt.