So, I have to say that I have really enjoyed this exercise going through and reverse engineering the LS7 engine. I found it easiest to model just one bank (4 cylinders) at a time. It enable me to look through the inside of the block and make sure I had proper clearance, etc. It just gave an overall better working environment.
After making the one bank, all I did was glue two halves together with the combine feature of Solidworks. Pretty darn close!! Obviously, I built in the cylinder offset, but overall this sure was a simple way to get in there and work through the details.
After combining the two, I was able to add in the cross webbing, bearing supports, and can start working on specific detail to the combined overall block (front timing cover v. bell housing, etc)... Still lots more to do, but this has been enjoyable so far.