Reliability is not a problem at all making 200 whp with a sohc - even a Y7, but I don't see it even nearly economical to pull that kind of power out of a Y7 head... it's just not a good head for performance - period! And sure you have to put in some good pistons, rods and other internals to make it reliable, but it can be done! And BTW - ALL sohc connecting rods are WHIMPY! It's a surprise that you can put 8 psi on a Z6 or Y8 and have the rods hold up, but I guess it also has a lot to do with that good old quality material that Honda uses in those rods. My last hatch had a built Z6 in it running on 14 psi(rpm sleeves, 8.5cr srps, pauter rods, etc.), but it cost me 3500 to build minus the FI. I think this time around I would build a B series up instead, b/c you can get more parts for them and the blocks can handle more power from the start. The bottom line is that you probably will spend close to the same money building the crap out of a D-series or B series, the big advantage is the amount of power you can pull out of a STOCK B series vs. a STOCK D series to begin with (better head design, stronger internals, etc.) In the end I'm still a big fan of SOHCs - they're cheaper, lighter and more plentiful - you don't need to have a B-series under your hood to go fast!