When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
If confident that the vehicle is original, the VIN should tell you.
Otherwise , you need to measure the sroke. Do a search in this forum and you'll find plenty of info. Or, if it's easy access, you can pull the oil pan and ID the crank.
If the engine hasn't been cleaned up really good, you should be able to find a yellow sticker on the driver side valve cover. This should give you your displacement.
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.