I did one of these 2 years ago on a 56 & just got through doing one on a 55 2nd series. On the 55 the 6 cyl. gearshift linkage won,t clear any exhaust you put on. You need to change to a v-8 shift linkage or 56 up. Even the side cover on the trans. has to be changed. You can,t use HEI. I use a crane electronic kit in the stock dist. Other than that the previous posts have covered practically everything.