Yep, I spent a ton of time messing with the desktop dyno. I had nearly identical findings as yours. And it will likely be right around 10:1. Stock l33 has flat top pistons vs dished on any other 5.3 so that bumps it from 9.5~ to 9.9. I decked the block .005" and will have the heads shaved .010 or .015". Also will be doing some porting so I'll gain se combustion CC's there. I'm looking forward to getting the engine running! Too bad I still need a looot of parts for the car so it won't be for a while