A 351 ia actually a common V-8 internal combustion motor made by FORD.
351 is the displacement in cubic inches.
That Ford truck has a 351 instead of a 302.
If it were a Chevrolet, it would probably have either a 305 or a 350 under the hood.
A powerful V-8 engie commonly provided by Chevrolet.
This 351 finna make your old-school smash nigga!