I used the drill guide and drilled the six mounting holes for the throttle pass thru. Used step drills to increase the center hole to 1 and 1/16 inch. The step drill caught a bit at the large size and deformed the firewall a bit near the small holes. Was able to bend the firewall back and clean up and deburr the hole well. Deburred all mounting holes and inserted the pass thru and screwed in place. For the next hole I drilled the two holes for mounting plate farthest from the center hole then upsized the large hole with step drills. This worked better as the firewall had more strength without all the small holes and didn't catch on the large step drill. Used the drill guide to finish drilling the other mounting holes. Deburred all holes and installed the pass thru.
