fortunately, the 364 and 401 have different deck heights so you can figure this out without pulling a head off.
notice the intake manifold spec at the bottom of this page:
https://www.teambuick.com/reference/...s_nailhead.php
364ci should be 8 7/8" between bolts while a 401ci / 425ci should be 9 1/8".
alternatively, the 364 and 401 have different strokes. you should be able to test this simply by pulling a spark plug and running a wire ( welding rod, whatever ) down in the top of the piston. measure how far the wire sticks out at TDC and subtract how far it sticks out at BDC and you've got stroke.
364 == 3.390"
401 == 3.640"
the standard engine for a 2v Le Sabre was a 250hp 364ci.
all 401s in 1961 should have been 4v carb.
https://www.teambuick.com/reference/...ine_number.php
Bookmarks