I found a 1970 Mercury Cyclone Spoiler with a Factory Boss 429 Super Cobra Jet, trying to validate because supposably this car might not exist. Heard then only 10 are known of, please advise!

The Boss 429 was not available to the public in the torino, only in mustangs. I think there are rummered to have been 2 factory prototype torinos with the boss 429, not really sure. I'm sure there are guys on this site that know for sure. the other motor you're talking about is the 429 super cobra jet. there was also a 429 cobra jet motor. and a 429 thunder jet. these were available in the 70 and 71 torinos. usually when someone mixes names or models like that they really don't know that much about fords and are trying to impress. anyway the 429 engines are not real rare, 7,000 or so in 70 and around 3,000 in 71. uncommon but not rare like a hemi or copo chevy.

I reread your post and saw you were talking about a cyclone. the info about the availability of the engines is right but the cyclones are rarer than the torinos. I have no idea of the cyclone numbers built.

In 1970, Mercury dealer's showroom literature for the Cyclones showed a Boss 429 engine option, along with the 429 CJ engine. I have an original broacher for the 1970 Cyclone. I have never seen a Boss 429 engine in the Cyclone and I was told by a few Cyclone experts that Ford changed their mind after the showroom literature was printed and it never happened. You may check with the IMOA club. They know quite a bit about the Mercury Cyclone.

There were rumored to be several preproduction Cyclones built - but none verified on my Cyclone Registry.
Please get the car's VIN# & we can check it out.
Thanks,
Rob
If you own or find a Cyclone/Comet (64-72), Montego, Torino/Fairlane/Ranchero (68-79), 70 ½ Falcon, 64-67 Mercury intermediate, or 77-79 LTDII/Ranchero/Cougar(74-79) in a junk yard or up the street please register it by dropping CMTR a note with VIN#, door codes (if readable), transmission type, color (in/out), stripes, options or what ever partial data is available. Modified or stock, running or parked. There is no charge to add a car to the list but CMTR must have the VIN number to chronologically place the car on the list and keep a car from being entered twice. The list will not contain the owner's name or address, just the state/country.

http://clubs.hemmings.com/cyclonemontegotorinoregistry/