Greetings David, from Germany!
May I first say what an unusual honour is it to be able to interact directly with you in-person through this forum. I have read all your books and regard you as a celebrity! 
I am a 9-year member and moderator over at the TDIClub.com forums, and am myself a powertrain engineer currently working at an engine development consultancy here in Germany, after deciding to take a mid-career hiatus and go back to school to undertake grad studies in engines. Day job aside, I have done tuning modifications and amateur motorsports (Solo 2, drag racing, track days) with my former daily driver (I am not native German).
I read through your concept with interest, and had a few questions I hope you’d entertain addressing. My first is a question regarding the swirl induced by the differently-sized intake valves- and ports: It would seem to me that, given the same valve lift, and what appears to my naked eye as a relatively small amount of port division biasing, the flow through the smaller valve would actually have a greater velocity and therefore momentum to influence the swirl. Am I missing something?
Second is a comment/question, that the importance and significance of valve masking cannot be understated in your concept. In fact, may I be so bold to say that masking has as much- or more of an influence on the in-cylinder flow-field than the difference in valve diameters. Now, I’m sorry for my newbie-ness and maybe you have already covered the subject in detail elsewhere (I’m just now reading up on the multitudes of threads here, having joined only today), but I would like to read your experience and thoughts on valve masking. Also, your stated increased tendency of 4-valve heads to “cross-flow” would seem to also affect hemi-heads as well (if not more so), and is a function of valve included angle and the downdraft angle of ports.
Third relates to my sphere of interest, and that is tuning VW’s TDI Diesel engines. Here, there are some rigid boundary conditions that need to be met: the valves are completely vertical, and there is no combustion chamber in the head per sé; most of the clearance volume is in the omega-shaped piston bowl. Due to the very close clearances the pistons come to the closed-valves, the valve timing does not tolerate much if any overlap; in fact, OE specs have IVO at 16 deg. ATDC and EVC at 16 deg. BTDC at 1mm lift – yes, negative overlap of 32 degress!!! I have designed a cam that tries to minimize this negative overlap as much as possible, particularly closing the exhaust valves as late as possible before the pistons slam into them, in order to minimise the substantial residual gas recompression work that I was observing in my simulations.
To make a long story short, the ports, valve timings and flow area on the TDI are clearly not developed for high flow (tiny valves, only about 8.5 mm lift, and helical ports to induce vital swirl for Diesel combustion efficiency). If the flow can be improved while maintaining swirl, there could be significant potential for this engine.
Lastly, I have been working on an engine design that would have a displacement of 500 cc per cylinder. My goal is to achieve a specific power output of 167 HP/L
naturally-aspirated! I have calculated that peak power would have to be developed at 9250 RPM and a BMEP of 16.1 bar (234 PSI) at this operating point. My question is, in your experience, are such BMEP figures attainable, particularly at such RPM without too much sacrifice at lower RPM? I have read Cosworth’s DFV engine of 1967 making 203 PSI at 8500 RPM, and Cosworth-prepared Super Touring race engines claiming 254 PSI (!!!) at max. power RPM.
All the best, I greatly look forward to hearing back from you.
Cheers,
Dave