I agree with Don. However, there are two other angles you need to be concerned about. Those are the angle between the driveshaft and the centerline of the crankshaft and the angle between the driveshaft and the centerline of the pinion. They need to be within limits also.

For example, if the engine were high enough in the chassis, it would be possible to have 5* down on the engine, 5* up on the pinion, and have the crank directly in line with the pinion. That would not be good.

This article gives some good ideas:

http://www.streetrodderweb.com/tech/...les/index.html