I just read on another blog that the US ECTA(East Coast Timing Association) LSR Speed Record Holder in 650 N/A pushrod, with his 650 Triumph twin, has dyno'd his bike at 60 hp at the engine(crank hp). This is a pure race bike, trailered to the track.
He has run somewhere around 122 mph in the flying mile on that bike, and holds the record.
Just FYI.
While the Trailblazer is about 42cc more than that, I think this engine will do better than 60 engine hp, even on a street bike.
As a side note, I showed him pics of our roller rockers for this application, and he wished they had that for his Triumph. I told him we could do his heads, but he wasn't willing to spend any money.