Some of these stories are getting a bit ridiculous. Most of the time I can just ignore it but I really have to say something in this case.
(1) Shelby had walked away from any involvement with Ford well before 1970.
(2) Cobra and GT were two different trim levels of the Torino.
(3) The 427 sohc was old news by that point, still available over the parts counter but not experimented with in production cars by 1970. A street trim 1964 Galaxy with sohc 427 power was built in an attempt to prove to Nascar that it could be a production engine, but that attempt failed as it was banned anyway. By 1966 the cammer was viewed by Ford as a failed experiment to dominate Nascar, and the drag race guys got all of them to themselves.
By 1970 the Boss 429 was everyone's focus as it had a chance to beat the Hemi and be considered a legitimate production engine. IF a sohc 427 '70 Torino was ever built by someone connected to Ford, it was a one time deal as a special request. Alot of sohc 427 powered cars were built in the '60s and '70s by private owners and speed shops. If this car was what you say it was (and I really doubt it), then it may have been a custom built when it was still a fairly new car.
(4) Assuming your '98 Ranger was fairly new at the time, I could see someone wanting to trade a '70 Torino for it IF it had something in it other than a 427 sohc. The 427 sohc engine is much rarer than the 426 hemi, in my opinion more valuable, and most likely by the late '90s the engine alone is worth more than a '98 Ranger.