Automotive and marine exhaust manifolds are not interchangeable, as the marine must be water-cooled.Originally Posted by kswest
Think of the load on a marine engine to be similar to driving your car in first gear ALL the time. A passenger car engine would never hold-up for very long under marine conditions.
That's why marinizers start with the heavy-duty truck engines.
Truck engines usually have beefier cranks, forged pistons, better rods, etc.
I'm not defending the price gouging, just showing you that in certain aspects you need better stuff.