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They are the same family and mostly it will bolt up. If you are putting a late block in an early chassis you won't have a drilled and tapped hole for clutch linkage.
The timing cover and water pump will fit, but the bolt holes in the head are in a different location due to the increased deck height.
If you are not changing a complete engine, you will have to come up with a different intake manifold and distributor.
If you are not putting it in a truck chassis you might have hood clearance issues and although it is only a slight difference, you might have exhaust pipe fit up issues.