I've been paying attention to the 8.1, and, I have heard a few discussions:

1. The Block is a standard Gen VI BBC with different Heads and Intake, so you could bolt on regular Heads and Intake and have a Factory 496 (or 8.1).

2. What you are saying, that is is based on the Tall Deck Block.

3. There is a Company that offers an carbuerated Intake to fit the Heads that are currently on the 8.1. (I can find it if I look a little)-

Don't know if you are considering performance upgrades, but if you are I wonder about upgrading the Heads for more CFM as I have heard that the 8.1's are not a great, high RPM flowing Head. Does anyone else know the truth so I can shut up?