Did you swap the SD motor in? The SD was only offered in 73-74. They listed it in the manual in '75 but it didn't meet emissions so it got dropped. They did have a 455 though in '76, love the Pontiac big blocks. I would love to get my hands on my uncle's '74, red with a shaker hood, 400, all original and low miles, has just been sitting in his garage for YEARS. That 455 bird (if all original) is one of about 7100 with that engine in '76 since it was the last year the 455 was offered. Got any pics of the rides?