http://www.atomiczombie.com/ct-raketrail.html
Your wheelbase will be lengthened slightly thanks to all that extra rake, your bike's front end will sit an inch higher, which will serve to increase trail (a stabilizing effect) as the frame geometry rotates about the rear axle and thus slackens both seat and head angle slightly, but the extra rake may null any trail you might have gained.
It's hard to know exactly what the net effect will be but you might not like how high your front end sits after changing to that fork.