Chainsaw Repair

Yes the California models were 45cc. EPA regulations in California are so tough that Husqvarna had to boost the displacement to 45cc to help offset the supressed muffler.
The 338XPT -XP is 39cc. Mine came with a muffler outlet so small that a pencil eraser could barely fit in it. I added a 9/16" outlet pipe at the bottom and kept the top one. Throttle response and power greatly increased. Harder on fuel though.

For someone just pruning or line clearing cutting small wood I'd keep the muffler stock and enjoy the better fuel economy. But with mine I cut some good sized wood with it and need the extra zip..