The M110 does have a noisy valve/cam arrangement, but too much noise could be trouble. Adjust the valves and check the noise again.
Also, if you go with the M110 it would be wise to check and change all the vacuum/air lines before you put the engine in the car. Doing this once the engine is installed is a pain, and the M110 is very sensible to vacuum issues.

As for the intake manifold: the original carb for this engine is enormous. I'm not sure you would get much extra space by eliminating the CIS. I'd measure them both carefully.