1965 coronet 440/ 4 speed swap

check your header app guide. 62-65 was different than 66/up. you may have to rebuild those headers you have to get them to fit. you could use them if you put a 66 up k member in car. an old super stock trick for weight transfer. b sure to look at your oil pan as 65 has to have pan that has the drop back between the 2nd and 3rd hole on pass side or it will hit k member. cool cars when done.