Originally Posted By 71 GTX
so you are saying that it really does not matter which size I use....its for my 71 GTX....


Well, a 143 tooth requires a larger bellhousing, which can interfere with headers...

With an 18 spline I would be determining what disc and P Plate you want to run. Discs are kind of limited in 18 spline. (I run a McLeod, I think C-Force makes them from time-to-time but they aren't always available)