Sweet, thanks for the numbers, Jon. I'll trade you for some of my own. I just timed my poor ol' VX-18 and the numbers are predictably soft:

Crank opens 43 ABDC and closes 52 ATDC for 189* duration
Boost 53 BBDC for 106* duration
Transfer 57 BBDC for 114* duration
Exhaust 77 for 154* duration

The construction of this engine is equally predictably ... quaint. Still great pinch, so no excuse NOT to port it. Not sure what I'll do yet but I'll probably try and correct some of the deficiencies while I'm at it.



Your porting hand looks pretty steady. Personally, I'd shape the fang so that the trailing edge lines up with the arc of the transfer port, like the attachment below. Would probably ramp the jet off the curve a bit stronger than just the fang alone. I'd also give more slope to the lower side of the boost port (though from the side view it looks like you've got a goodly slope on there), and I'm not sure about the three fangs on the boost port but I've seen it done that way on a few examples. The inlet to the crank still looks a bit abrupt, but it might be the photo. I'm still a newb in modifying these engines but I've ported a few cylinder heads... like that means anything.