Very nice car! I read that the 7.0 litre engine in the C-6's had a cubic inch displacement of 427.8, however rather than round up GM wanted to designate the motor a 427, symbolic of the 427 of the past, thus it's deemed a 427 and not a 428!
I'm not going to debate automatic transmissions versus manuals because there are positive attributes for each and I'll leave it simply to personal preference, however I've always been partial to manuals. I feel your more at one with, and connected to the car with a manual. I also read that although automatics outsell manual Corvettes making up 80% of total sales, interestingly in Germany Porche experiences the opposite ratios.
Anyhow you've got a beautiful looking Vette, enjoy!
Cobra