What are the specific issues you are having?
Right now I am pretty set. Got an adjustment to be in my lane better. Got some solid warning that I was able to research about IH on Youtube. Saving me from royally messing up the crank and piston balance on my saws that are coming.
I'm still wanting to ad Muffler Mods to my saws but am still unsure as to their benefit except for Egans proofed 28% gain for the Echo CS-2511. So I just bought his pipe. I am gona see if it matches the holes and right exit for the 5+ 25cc Zenoah clones I have that I use for limbing and to keep in the car for mountain drives.
I spent some time with a pro builder today in person who has been porting back to the 70's. Great and helpful man! He set me strait on pretty much everything my recent "discovery posts" were trying to ferret out.
So I am down to gasket delete, polishing intakes, maybe some widening a few areas without effecting any timing and muffler mods. (Each per saw choice will be different. I will study the specifics and have more educated questions then.)
Picked up a cheap Chinese Cylinder and Piston to study just what I can do for "work saw" performance and practice with before my 372xt saws get here.
Other than that I'm doing good; feel I have got good counsel and can do a game plan. Organizing all my tools and all saw stuff so I can hit each project without trying to find all my old gear I packed away.
I would like to find a reasonably priced Muffler mod that has proven 15%+ performance gain ... for the 372xt.
Really learn why (other than heat dissipation) what makes one better than another. No pipes for the big saws ... but likely want to have them for the little saws or muffler mod for the medium sized saws.
OR - learn to silver solder and braze all the mufflers myself. (I bought a few spares of them as well, so I can make my own muffler mods)