You will have no issues with the Modelhaus 63, its a direct repop of the Johan. The reason the hood is thicker is because the body it was molded from is the promo, and it has the screw posts under the hood and trunk. If your cutting the hood out, keep in mind you will have to add the radiator support and stock inner fenders. I suggest using the 68 or 69 Roadrunner, or the 70 Coronet chassis and front stub with the K member. It will involve a little messin with to get it to fit, and you will have to shorten the length, but the wheelbase should hit perfect. I use them in all my early Mopars, they offer alot more detail than the stock Johan chassis. I do have a mint Johan 63 kit, but im sure you dont want to spend $200 for it. lol Best of luck, and PLEASE show your progress!