Here are some of my favorite kitbash's. A pair of 69 Boss Mustangs. The yellow one is a 69 Boss 302!! I used the 69 Mach1 kit combined with the 70 Boss 302 kit. This one required lots of bodywork to pull it off.
This one is the 69 Boss 429. Also using the 69 Mach1 kit with the hood scoop and engine from the 70 Boss 429. This engine is a tight fit as it is 1/24 and the body is 1/25. Only body mod was removing the molded in battery. Cutting the hole in the hood was tricky as it had to be right on. The air cleaner sits in it!!