You can run the carb either way.
I would be better to mount it the way you stated.
Just need to buy a long throttle cable or other linkage ideas.
If you want a carb spacer I would run a four hole type.
What kind of engine is this going on? I'll guess it is a Chevy 250?? . Type of build?
The Clifford manifold is quite large( volume inside) & depending on your build & size engine you really should not need to add any more volume to the intake manifold.
The Offy will give you better street manners, throttle resonse etc.
Milage will drop with a Clifford manifold.
