Putting a 2.3 in a 71 to 73 is not that hard, just have to take your time and not butcher up the whole thing, if you do not want the turbo and not the wiring use the 84 up turbo block and a early 1980 carb turbo, they are still out there and not to bad when set up right, they used the 9.1 Pistons, the 84 up used 8 to 1. There is room for it on the 71 to 73. Only you will have to use a hood scoop , yep the carb is much higher, unless you cut off the carb mounting pad and use a side draft webber to hid things, Back then I used the hood scoop that came off the 80 mustang , looked good,