Need to drill through the T-405, Rib and T-411. Care must be taken in placement of the rivets so they don't interfier with the gas line fittings. I'm using a flop tube and it attaches in the center of these 6 rivets with a 9/16" hole. You can't see it but I traced the gas line fitting on the T-405 to see the clearence between the fittings and rivets.
I marked the hole locations on the T-411 and camped all 3 pieces together.
Image 1 shows them clamped together and the blue hole locations.
Image 2 and 3 show the drill press setup for drilling the 6 rivet holes.
