I have an '89 with 306,Y303 aluminum heads, B303 cam and Vortech V3 at 10psi. I just changed exhaust and have a stutter or misfire under hard acceleration. I felt it once in awhile with the old exhaust, but this setup flows better and it's very noticeable now. Currently running Autolite 104 plugs gaped at .045". I'm sure that's too wide, but should I close the gap to .030" and try that or should I run one step colder plug? And what gap on the colder plug? @a91what , would you be able to see if it's a miss fire if I got you a data log?