Tim W can add 100 hp by changing the cam and the carb. But then the torque band moves up and the rear gear needs to change. Doing that makes the car faster at a particular road course, but then the car becomes a lot less street friendly. The goal last time was to go 160 mph on the front straight at PIR and drive it home.

If you want to be able to go faster than that and still drive it to the track you need to step up to a 5 or 6 speed trans. That wasn't in the budget for the current thrash. If his budget finds another $10K then it is fairly easy to add power, gear and a new trans. There aren't a lot of transmissions (maybe zero) that are easy to shift, reliable at 600 hp, and fit in an A-body. Maybe the new Passon box will work in this application but right now it is too new to know for sure. The Keisler stuff might have worked but there was always a lot of negative news floating around and now they are bankrupt. A T56 requires more fabrication than Tim was up for. Plus they are heavy and the 6th gear isn't really that useful.