Contact some of the well known Porter'sI see... well I'm in no hurry whatsoever, I have 5-6 saws that fill the gap and two of them aren't even fully broken in yet (462 & 7900) but I haven't owned a ported saw yet, and would really like to change that... My 372xt is my first choice to have ported I decided, I even have a brand new OEM cylinder, and the lower end is still in great shape with new seals & bearings a bit over a year ago.
the cylinder on the saw now is slightly low (132-136psi) on compression due to a heli-coil in the spark plug hole leaking a bit currently. I got the saw for a little bit of nothing because it had a stripped plug hole & the local shop quoted the guy 400 bucks to put a new cylinder and piston and crank seals on it. and while it runs OK now, I would love to see what a good porter could do with a new cylinder on this otherwise decent saw.
In the past i had them port cylinders only
On cases they already had.
They can adjust for gasket or no gasket builds
And they all have their porting number recipes for different saws
They use.
The guys that ported mine are booked solid.
There may be other's willing to do it.