Equal angle or angles that parallel each other is the same interpetation.This is the best situation when when the trans is higher or lower than the rearend.If your building a chassis then it is best to locate both componants as near as straight as possible and set for the torqued or loaded change.As far as circle track cars are concerned,they shouldn't be compared to a drag car.A drag car should be built as stiff as possible and travels in a staight line under constant load,a circle track car chassis has a flex factor to contend with as well as loading and unloading of both the chassis and drivetrain.To apply circle track tech to a drag car would like to try and breed a poodle and a tiger,some thing bad is going to happen.