I don't see why it would be a problem, the 80's s-10s had a 4.6? basically a v6 made like the old 350 with 2 less cyl. the s-10s are cheap, reliable and there is a lot of em with alot of upgrades. chev's are easy to modify and have alot of space. maybe use a stick to drop some front wieght and mess with the diff gears for better pulling or highway use. gear vendors makes a nice od and you might be able to fit a chev manny tran since the mbs were borg warner. if the block is long salvage two old honda goldwing radiators to split the front and rear mount the battery. most mb people don't want to modify (they are great cars) but there is alot of neglected vehicles with salvageable parts that are rusting to death anyways. check out off road mini truck sites as well as mb truck info like the uni-mog which i believe uses the 5cyl. just take your time to do it right so when its all said and done and everybody feels dumb who said you were crazy. everybody still thinks i'm crazy but i am the first one they ask for advice.