am i missing something on this 318?

Yes you are. That happens to be the incredibly rare "rare earth red" version of the 318, which was installed by Chrysler for those customers who later wanted to upgrade to a 340. This was officially known as the "318 update" option, and came with the limited "expandable" exhaust manifolds which when bolted to a 340 automatically detected the larger ports and adapted themselves.

Also, this engine came with the rare 273/318/340 crank, and came with a complete 340 top end stored in a special crate in the trunk. Unfortunately, no one has ever actually SEEN these crated top end pieces, because every single one known to exist was stolen by employees before the car ever got to, or left, a dealership.

The seller is incorrect on one minor point, and that is, this does not have OEM A/C brackets. Nevertheless, these rare versions are worth a LOT more than the asking price.