got the 383 tuned-ish. its running but we were having issues with it misfiring at around 3500 rpm. he told me to pull the plugs and replace them with tr55 gapped at .050. now it runs like absolute ****. the only thing she does well is idle. any thoughts?

 

the original plugs he put in where tr6 at .035

 

I highly doubt its related to the plugs unless one is physically damaged. Ive run 55s, 6s, and now 7s with no noticeable change from the stock plugs.

 

it ran WAY better with the 6's at .035. the issue is gap related. but the wider the gap she shittier she runs. my question is based mostly on gap than the temp of the plug.

 

it seems my google mechanic skills say that i should be around .035 but this is based on a LT1 383 with 11.2:1 compression. not the best comparison but in not a licensed ase certified google mechanic.