Grigg,
I thought about that and did find a remote air cleaner setup off an astro van or something like at the wrecking yard. I saves me maybe 2 inches but my tunnel is so low and narrow and I am not giving up any leg room for the driver and passenger now.
My right leg is straight out in front my hip sitting square in front of the steering wheel with the gas pedal off to the right and it looks and feels totally normal. I have the floor board 1 inch above valve covers so I could fit a PCV in it. The floor boards still come off as the orginal truck did so the engine is intirely accessible from inside the cab.
My next COE truck will be a mid engine (in the bed) with no tunnel.
That is one wicked looking V12...Maybe I could convert my entire bed on the next truck to hold one of those engines?