question about engine noise

[1979C20]

I replaced my distributor, and set my timing by ear to where it was at the same RPMS as before I replaced it. I think the timing is off, but I dont know if that would cause this, When I hold my rpms at about 3000, i can hear a little thud in the exhaust, almost like a miss fire. My trucks kind of runnin like a dog. My number 2 plug wire is a little melted and the insulation is showing, I dont know if it is miss firing because of that? I dont know if its miss firing at all. And, My plug were fuel fouled when I checked them last, which is when I replaced my header gaskets 2 weeks ago.

[VileZambonie]

Replace your wires and set the timing.

[1979C20]

Okay, and, since my plugs were fouled, should I adjust my mixture?

[VileZambonie]

correct the misfire first and get the timing set. From there see how it's running.

[1979C20]

Okay, Can I use a wire brush on my spark plugs to clean the carbon build up off, so I know if the foul again? And thank you for the help.

[VileZambonie]

If it's carbon build up I would say replace them and make sure you are running the correct heat range. Do you have a pic of what the plugs look like that you can post?

[1979C20]

Not right now, but ill snap a pic as soon as I can.

[topp]

Also, make sure they are gapped right.
I had a plug that was not gapped enough and at idle, gave a misfire "sound".

[1979C20]

I gapped all of the plugs while the engine was still on the stand with no cam. Haha. Hoping to figure her out today

[bake74]

     x2 on vile said, you need to got the raght plugs and timing before you can diagonois any other problems.  Make sure your plug wires are good also.

[thirsty]

Also check for a cracked insulator if you put the motor in the truck with the new plugs in it still maybe one is broken.

I had a similar problem once with valve adjustment. Michelob Lite was the real problem but I had one valve adjusted wrong and it took me a while to get it right. That was when my old school mechanic dad was still alive and he diagnosed it from his chair. He got sick of listening to it while we tried to figure it out in front of his garage and came out and set us straight on it. His words of wisdom were "it didn't run that bad before you boys changed that cam, it must be something that you did. If it were me I would check the valve lash" and walked back into the house. He was right. Maybe not your problem but if all your plugs, wires, timing, plug heat range, float level correct, ect. it might be a place to look next.

I would start with new plus and wires first though.

[1979C20]

Installed the engine with the plugs out, ive pulled the valves cover at about 1k on the motor to adjust the one valve that was ticking. Only the number 2 wire is melted, all 4 odd bank plugs have build up, I havent checked the evens because I didnt need to remove.them when I did my header gaskets. I know my carb is set too rich, for sure. And im almost certain my timing is off. So, I have a list of things to do, and I thank you all for he input, I gotta try to get some time at my buddies dads shop to time her, because my dads timing light broke. Ill get back with details soon.