727 Build for Mid-10s

CudaFactHackJob said

All the 6-7 plate directs use smooths that I have seen. I thought the grooves were for cooling. But Red Eagles can take the heat. If the grooves were for hydroplaning, then they would be radial.

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Posted in Tom Hands torqueflite book is a pic of a smooth and a grooved clutch disc. It specifically states that smooth clutches are to be used in the rear clutch only and the parallel grooved are to be used in the front to allow oil to exit quicker in rapid clutch applications.
Both styles shown were red altos and it said both styles are available thick or thin.