Chassis dyno numbers can be really weird with an automatic. I don't think I'd worry about it just yet. How does it drive? How is the Sniper working so far? Are you controlling the timing with the Sniper?

Did you record data logs for each dyno pull? If so you can open up the config file on your computer and then play back the data log. That will allow you watch what all of the sensors are saying during the dyno pull. I'd pay attention to the AFR and MAP to see what they say. Do you have fuel pressure hooked up to the Sniper so you can data log it too?

I think you'll have a great combo once you get it all dialed in. If you want to make more power down the road you can get the heads ported and go up one size on the cam and you'll be around 600 hp at the flywheel.