Hi guys I have been doing maintenance to my new used truck. Last oil change I drove the truck around 50 miles and I started noticing burnt oil smell and alot of smoke coming out of my exhaust pipes as a accelerate. As I heard rattling soon I started to figure where the rattling was coming from. Im not a mechanic and this is my first used vehicle I have ever bought I freaked out. So today I decided to unbolt the cat from the exhaust and sure enough a lot of dust poured out so I saw big chunks of carbon look alike I guess the honeycomb as Ive heard people call it. I cleaned it out and vacuumed all the dust. Its a weekend so Im drinking so I would not drive it until tomorrow to see how she feels. Im worried I might have damaged the engine as I only have driven it about 300 miles. As I said before I bought it used the guy I bought it from had swapped the engine and had driven very good. Any advice or suggestions would be greatly appreciate it. Should I keep driving it as is take it to get look at Im thinking about replacing manifold with jba Ive heard its the best route. I do think it has oem manifolds.