your goal is something cheap and light, right?

What is the cheapest aluminum-block V6 you can get that has a fair amount of horsepower and torque to move a heavy MB?

I wonder if a 3.5L Chrysler V6 would fit... You'd need the engine and trans from a 300 or Charger but they're FR so it'd go in with driveshaft mods as long as you have clearance otherwise, and that's 250HP stock. Not that the M110 is weak but you're shaving off a lot of weight there, adding about 50HP, and getting a modern 5sp trans...

Or you could shoehorn in something like a 351 windsor... now that would be something else if you get one that's already been bored and has a good cam...