hi 7o chevelle do i take off the carpet firewall guard and push carpet underneath it then reinstall the guard? and also how much carpet to leave under the sill plates? thanks storm

You should soundproof and insulate under the carpet before you install the new carpet.Cost is around $40.You can push the carpet underneath the firewall.Place the sill and move your carpet on it and I usually measure and cut the carpet so it sits in the middle of the sill. Use a ice pick to line up the holes in the sill. graemlins/beers.gif

al i soundproof it and add insulation to it already i took off the guard and put it way up under there then put the two screws back in i just really didnt know how far to push the carpet up .the sill plates i didnt know if to go as far as i can or half like you said i just didnt want the sill plates to sit uneven. what about the back? past the bottom seat lock in brackets or just up to them also?