Hey guys, I’m new here and to forumns in general. I have an 87 f350 with a 460, edelbrock performer intake, and 1411 carb. I rebuilt the carb the other night after a few years since the last good year down. I still had a good hesitation when taking off so I called edelbrock, after getting some basic tuning dialed in and me mentioning the previous owner had installed a 1” and 1/2” carb spacer between the manifold and carb edelbrock said get rid of those immediately. I did, but this manifold had a factory hold on the passenger side next to the carb base for emissions. The spacers I removed had a pipe plug in it to block it off, so I refused the 1/2” spacer and bought an Alan head pipe plug to cap the hole, edelbrock said while you’re at it knock he carbon buildup in that hole down in the intake it’ll just blow out the exhaust.. which if I was using my head I would’ve thought about it having to go through the exhaust valve, etc not just falling out of the header. I got it all together, started it, adjusted idle slightly to 800 rpms, bam. Knocking.. this motors never made a noise before, 35-40 psi warm oil pressure, 50-55 cold, runs great, but knocking sounds like above one of the two back cylinders on the passenger side. I ran some Seafoam through the pcv and carb and oil to see if maybe it was just a little carbon debri needed to break up.. nothing. So before I pull anything back apart I’m hoping someone has some recommendations? I’m assuming that carbon I knocked loose in the manifold emissions hole got down inside of something? Unless my truck just randomly decided after doing a carb rebuild among all the other repairs lately to start having a lifter knock.. any suggestions are appreciated