I have a 1969 Mach 1that I purchased two years ago and it is equiped with a 4V 351C bolted to an FMX trany and a 9" open rear. Is it stock, I don't know but thats the way I bought it? The numbers match the equipment and engine size, assembled in San Jose in late August. I found it stored in a pasture with weeds growing through the engine bay, no hood and the interior stripped out. All that remained were a shell with glass, doors, dash and steering wheel, 4V 351C, trany and 9" rear, fron suspension, grill and fenders. I pulled out with my pickup and loaded it on to a tow dolly, payed the owner $750 and .pulled it home. History of the Mach 1 was sketchy and the owner bought it as a runner. Disasembled it completely including the interior. He told me that he purchased all new interior and supposedly had everything new and still in boxes but could find the boxes. Since the car was in a pasture a certain cow gave me a lot of grief while I was pulling it out o the pasture. The cow had grown quite attached to the car and had bashed in the doors almost distroying them by rubbing and mooing and other things up against her "Tang" Original color was that Mint Green but it had been painted over with that bright orange. Did it originaly have a 4V 351C...does it really matter? And isn't something to speculate about.