The 440 and the 460 use the same cover. The part number is 1128 140 0801. My dealer couldn't find it and I had to give him the number. No modifications required to mount - they just bolt right on. They say it adds 1/2 hp, but it sure feels like more. Lots more grunt. I put a dual port on the 440, 460, and the 660 and it really makes a difference. I have heard/read here, that opening up the stock outlet hole as well will add even more. But I haven't done that yet out of fear of making the saw too loud. Want to make sure I stay friends with my neighbors.
To adjust your carb use a tach to set max rpm's @ 13,500 as a starting point. If you don't have a tach, you can tune by ear. Better to use a tach, though. There's lots of threads on how to adjust your carb if you do a search. But be ready to spend some time sifting through the tons of information on carb tuning.
The next step is mild porting. I haven't gotten into that yet, but it sounds like fun...:greenchainsaw:
