To bad there isn't a lot on info on the internet as far as Indy Buicks go. Buick dumped more money into the Indy program than they did in the NASCAR motor program. Both supported the Stage2 parts. Pick up a Buick Power Source Manual for some specifics for some of the parts.
One of the more noted names of teams running the Buick was none other than Kenny Bernstein. Yes the TopFuel King Kenny. Anybody remember the lame ass tech clinic from around 90-91 that KB put on at the GS Nationals? And McLaren who did the motor devolpement for the GNX built a lot of these motors. Bruce Allen the ProStock driver did a lot of head porting on these when he worked for McLaren. The weird bellhousing is a piece that most if not all of the Indy type cars use. It supports what is refered to as Cosworth Drives. This was a system devolped back in the 60's by Cosworth for the Formula 1 cars which incorporated external pumps for the oil and cooling systems on an engine. They are still used today. Somewhere I have a parts list for the one used on GMs Aurora Indy engine.
Up until a few years ago the Stage2 Buick was used as the spec motor for the Indy Lights series. But it was a NA motor. They were built exclusively by George Montgomery out of Ohio. Yes the same Ohio George that ran Gassers back in the 60's and 70's. Funny how it takes a drag racer to make one of these motors to fast.