Just bought an 02 440x and performing the low compression dome insert swap. Changing the jets to 310 pto and 300 mag. Also disconnecting the octane switch. Has anyone out there done this before and what advice can you give me? I want to trail ride this sled and was wondering if I still have to run high octane fuel. Also, what other hints or advice can be given on this year and model sled. Thanks.

Good choice on a great sled. Your on the right track, low comp domes with a #3 base gasket. Jetting is good. 92 octane will be more than enough. You could probably run 87 but better safe than sorry. get a Dynamo-joe clutch kit. You will not be dissapointed. The only problem with this sled as a racer was that the rear shock was too stiff and would hydro lock at really hard 100 foot landings. if it has had the updated valving it will be fine. Other than that, pull the cord and go. Enjoy.
and welcome to the forum.

Rad Chad, Thanks for the reply, What if I run the existing base gasket? Will it affect performance that much. It is clutched and has had the rear shock service bulletin done. Thanks.

You can run the existing gasket but to get the most power from the low comp domes you should run the #3. Stock gasket usually is a #7 which is pretty thick. While you have the head off the base gasket is easy to change. Also if it is clutched, you may need to tinker a bit with the low domes. You will lose some power and the clutching will notice this. You will most likely need to pull a little weight out of the pins.