Look at the front motor mounts. If it's a 250, they will be directly across from each other. The mounts on the 292 are offset, with the passenger side being toward the rear of the truck. The harmonic balancer (crankshaft pulley) is much larger on the 292,also, but you'd need the two engines side by side to do a comparison. Mounts are the simplest way to identify the 292 quickly.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
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