I saw some that were not licensed from Ford at Barret Jackson last year. The motor took up the whole engine compartment. But it was hooked up with a lift and different colors. they were going fully restored for 55 - 60K and I thought those were ridiculous expensive. So I bet if you go to Barret Jackson you can find one for cheaper.
I used to have an original half top 1974 bronco. I instantly blew up the motor, and dropped in a 351 Windsor. I bought it in 1987 for 400 bucks, and it had a bad front bearing in the transmission. I stayed up all night the night I bought it, and pulled the transmission, rebuilt it, and reinstalled it.
it was truly one of the best rigs I ever had. I ended up selling it to a buddy, a few years later, and a month after that it got stolen. Never to be seen again. It was midnight metallic blue with a factory white half top, so if anybody sees it let me know we are still looking for it.