no,the 455 did not come in the birds till 1970.my persomel opinion is you dont need that much engine unless you are planning on racing it.i have put a 350 in my 69 and i can smoke the tires off the rims with it.it is all in what you want.there is such a thing as over kill.with the price of gas now,,i wish i put a 6 cyl in mine now.