I use the aluminum/steel drum. As far as cost goes it was small compared to all the $$$ I've spent on that old car. I broke a 8-3/4 gear set once and the trans was filled with small aluminum particles. I never even took that transmission apart, it's still sitting on a shelf because it's the original for my Charger. I expect the O/R clutch spun in the case. I wouldn't use the aluminum drum because I have a problem with using aluminum for ANY wear surface. It just doesn't work well in that situation.
I talked to John Cope yesterday about that drum. He said he had one in the shop when they first came out. wasn't impressed with it and thought it looked cheesy. ...
That technical analysis is way beyond "cheezy" I bet he had something different to sell you.
