79rustyk10
3/4 ton status
The 400 block has siamiese bores, so there is no space for coolant to flow between cylinders, this is why they have the extra "steam holes" in the deck and in the cylinder heads. No other small blocks had these as the water jacket seperates the cylinders. The siamese bores in the 400 were required because GM wanted to keep the same bore centers as the other SBC engines for interchangability of other components. Just think if Ford had the ability to think like that, they would have what, 3 less different engine families, 2 less bellhousings and god knows what else.
