Have you considered a remote set-up? those can be pretty neat and tidy.
With your engine already having a higher compression-ratio,you sorta have the bottom-end covered and you can use the longer pressurized return-pipe as a form of charge cooler, or hide it in a Lake-pipe.
Or how about a 2-stage system?
One thing that might be in your slanty's favor, is the actual Force on the top of that 3.4xx" piston when the ignition fires. Whatever psi is there, the actual force would only be 85% of what it would be on a 4incher. I wonder how you could exploit that, with the super-long stroke?