Will a Chevy 400 interchange with a Chevy 350?
Chevy 400 small block ,and 350 small block are the same block
and they are interchangeable.
Essentially this person is right however, the stroke on the 400
is different, with a 4.00 stroke. Also, there are some subtle
differences, such as either the presence of a third freeze plug on
the side of the engine block, or not having one at all. The bell
housing is the same and you can make a larger engine out of a 400
block. Due to the fact the bore and stroke is the same dimension.
also you will need the flywheel or flexplate off the 400 because
they are externally balanced.