2009 polaris dragon 800

I have a 2009 dragon that I had recently just did the computer upgrade new pistons etc.. the whole fix it kit. The sled at half throttle runs fine but when at full blows a head gasket is there anyone with any ideas on how to dial down the turbo maybe do you guys think that may be the problem or any ideas?
Im running a attitude industries box with a sps 91 octane head and a garrett turbo.
ideas on what boost I should be running etc.