Sorry Lee, I would not be optimistic of your achieving a 95Db track day noise limit with a 396 engine slightly modded as you say yoiu have, AND that will rev normally in actual driving use. Especially if you are only at 108Db at 3500 at present. I doubt anyone could succeed with that target. There are plenty of track days with 105 Db static test limits and that should be acheiveable but remember the static tests are at 3/4 of max rpm so unless you car redlines at only 4666 rpm (I doubt that!) you need to test at a higher rpm level. I do know of a silencer system that was used on an engine with similar capacity to yours but heavily modified that was used to pass SVA so if you wish I will let you know who has it. I don't know if limits have changed since SVA became IVA though.