It says they "could" come with a 383. They came with pretty much everything.
"The Dude Sport Trim package was clearly more fun as far as options and looks went. The body length, C -shaped side stripe fit the contours of the trucks cab to Sweptline box and included the Dude logo. The truck was based more upon paint and tape appearance upgrades rather than comfort or engineering advancements. A good majority of the Dude pickups were 1971 model year trucks, so a truly rare find are the 1970 model years. Engines for these trucks included the 225 slant 6, the 318 small block V8, and the big block 383 V8. The Dude package could also be ordered with options like air conditioning, and bucket seats with center console."
