I think the timed run is as good as you can get for seat of the pants as long as you do what you say you are doing like record throttle positions, temp, etc... but I still think a dyno would be your best gauge if you can get one to use. Most guys I know with them will run anything as long as you have the cash to pay them.

When my friend Vic ran my SM he was amazed at the TQ and HP I got out of a stock 790. He normally runs HD and S&S HD knock-offs.

I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!