Top of line well optioned. Price getting low. Under dollar a pound. Says "429" perhaps "428" which was offered in 66. http://seattle.craigslist.org/kit/cto/5153244792.html
Might have replaced the 428 with a 429 from a later Thunderbird or something. He did mention 'Thunderjet' which was the 'name' on the 429.......
I'll go with the above. Dust in my attic now but I'm sure the 429 'Thunderjet', and or all 429's came out in the 1969 model year. There was a short lived 410 in the engine family along with the 428. I know the 410 was still there in 65 but not sure about 66...again dust in my attic. But dang, there is something about this 4 door brick, black on red I really like, I'd drive it