You will be able to tighten the stock header nuts through the opening in the front of the cowl. Don't make your holes in the cowl too large for the HS needel, low speed needle and muffler pressure line. They sell nice looking rubber grommets at your LHS that look really nice. After I located all of the points with a small drill and confirmed them, I just opened up the holes with a rat tailed file large enough to accept the grommets. FWIW it looks really great when it is finished.