Jay Bookman, at the Atlanta Journal Constitution did a very simple analysis of the benefits of Reagan-Bush style tax cuts. He compared the growth of investment and growth in the low-tax Reagan-Bush years with the higher tax Clinton years. Read the piece to see what it shows.
No, it's not conclusive. There were many factors other than tax rates at work. But, if the tax cuts really did have a big effect in boosting growth, they would counteract most of these other factors.