Here's a link to a pretty good artical on Pinion angle. http://www.buickperformance.com/Pinion.htm

Bill Currie also mentions in his writings and in his recomendations when you purchase a rear end from "Currie" that most single u-Joints have a working deflction of 3 degrees and they always strive for no more than 2 degrees. It's good solid advice I think but a little common sense is good as well.

RS