an LT-1 would be a great starting point, but I'd suggest getting something other than a GN, there are enough GN's and T-types that have rusted, wrecked or been smacked to get the critical performance parts off of them and GN's do have a bit of a repuation on the street so if you are going for something to sneak up on people with, get a Regal. If you do want to go LT1 get a Corvette one if you can, they may be more expensive but they make more power, have 4bolt blocks, have the correct accesory drive to drop right in, and make a much better foundation to mod on. Get a 95 or later one if you do get anything else since they have the redesigned opti-spark and converting from a stock OBDII system to an OBDI simply means only using one of the 2 Knock sensors and deleting the rear O2 which you would probably loose with headers anyway.