This is how I have my Dom set up .. you can turn over the adapter
to run the 750.. if you want a spacer put it under the adapter.. this
is 2 intakes set up differently.. 1 is a W-9 and the other a W-5
EDIT
How tall is your spacer plate.. I have run a 2" tall spacer under the
adapter.. your not looking for strength .. your not lifting the engine
with it.. you can lift the engine going straight to the intake bolts(carb
bolts but I dont do that