Joe,
If that's the only change you know of to the car, I have a hunch that since your RPMs are climbing at a much higher rate than before that you might be experiencing point bounce. It's also possible that you're just revving higher than you're used to (by accident) which is producing the same effect. The first thing I'd try is a fresh set of points.
Flogging a car in the Spring..... Geeeze, these kids today........
