Have a 283 in question. Back block casting number is 3731548. This indicates a 283 from 57-61.Staggered valve cover bolts seem right look to be standard heads for the day. The exhaust looks like 55-56 passenger but considering what it was in that would make sense to clear the 4wd. There are no side motor mounts so that indicates a 57 283. Front pad number is FI008F. Here is the issue I’ve never seen a 57 that had verticle bolts for a starter.This was in a Willy’s pickup. Had a fancy for the day cast trans adapter that allowed it to be bolted to the stock trans.