Question?
If you have a convertible body and a coupe frame you will need to add the number 2 body mount as a coupe frame will not have it..
The 67 frame parking brake differs so you will need to address that.
Also the 63 had seat belt reinforcements/floor supports at the inboard seat belt locations but you do not need to add them if you retain the seat belt cables on the 67. No seat belt cables, then you may have a problem purchasing seat belt cables from the vendors as they may not be currently available. You could weld in the 63 inboard supports and stop there. Optionally you could modify the 67 frame gusset at the kick-up to use the late 64 bolt in arrangement for seat belt reinforcement. You may have to drill a hole in the outer belt mount and through the body so the bolt will pass through.
You may have to fabricate a 3/16 brake line for the rear brakes if using the 67 brake line routing but it may not clear the body where it transitions upward at the rear kick up gusset, This is because the 63 body does not have the floor pan relief for the larger 1/4" rear brake line used on 66-67, or use 63-65 3/16" rear brake line and routing. If the larger rear brake line will clear the body you could use 66 brake lines if staying with a single circuit brake system. If you plan to upgrade to a dual circuit master use the 66 power brake lines, you could use the 67 brake lines but that will entail using the pressure differential plumbing (this is not a proportioning valve, way different) which you don't need. The 67 front cross member uses two bolts and retainers to secure the front brake line so the front cross member will not have the center hole for the single spring clip used in earlier years. Your choice use a 67 front line or drill a hole for the clip and use a 63-66 front line.
Finally, check the frame for straightness before doing any work and be sure to check the rivets on the body luggage stop and replace them if necessary. There maybe other details I'm missing and if I have something wrong I'm sure members will make a correction.









