From Wikipedia: "The 366 Big block V-8 (6.0 L) gasoline engine was used only in Chevrolet Medium duty trucks and in school buses. It had a bore of 3.935" and a stroke of 3.760". This engine was made from the 1960s until the mid-1990s. The 366 used 4 compression rings on the pistons as it was designed from the very beginning as a truck engine. The 366 was only produced as a tall deck engine with a 0.400" taller deck than the 396, 402, & 454 short deck big blocks." This means that the tall deck puts the heads further apart. This can be a problem in a narrow engine bay and header clearance is compromised. The intake manifold for a raised deck is wider. The pistons are going to be heavy.....and the engine will be a slug in stock form or mild tune. Gas mileage will most likely suck compared to a small block 350.