You mean to say you don't want to add the hump to the hood too?
The shorter 4 cyls do sit further back so there is more room due to less slope of the hood. You might get away with it. The water neck on the bell housing side is also present on the vw/Audi 1.8t. There is space beneath the OEM outlet on the Audi head where you could relocate it with some machine work to create more space and blocking off the OEM port. Similar to the Mitsubishi, you would possibly need to whittle a solution out of a block of aluminum.
Found this from a 924 swap in the UK:
This is the vw/Audi 1.8T...