[Adger Smith]

The lightweght vs heavy is something I have worked with many of my circle track customers. There is no HP there in steady state or controled rate dyno tests. All you get is better acceleration rate.
Ouicker under load. In a drag car that is the initial pull off the line and at each gear change it accelerates quicker. Liteweight rotating mass is quicker down the track, no more HP. Use the cast crank in your stocker r SS. As noted in previous posts aftermarket cranks are not legal in S/SS.