On other than originals,I made a set of aluminum offset adaptors, so you could put the
older 77-78{pre CV } carbs onto the later 1980 and up heads on CB650's--CB750's
{intake spread is different} so they could be slid on using the 1980and up
rubber boots, and as the pre CV carbs are shorter, could still use an airbox.
off the older model bike to match the carb intake.
the bike{ cb750c, } still running great 3 yrs later ,he just didn't like Cv carbs,
and didn't want to play with the heads.
Bruce