Now I know why 904 was having issues

Chryslers clearance specs are pretty generous. Back in the day when I was doing Powershift trannys, the rule of thumb was .010" per lined plate, minimum.
I like to set the hi-drum on the tight side of the spec, but often let the forward drum fall to the high side of the spec; afterall the piston has plenty of travel,and it has that big old belville on it, and it only engages once when engaging any forward gear and thereafter remains engaged in all forward gears. And I'm kindof partial to that slightly delayed engagement into Drive, cuz it's easy on the overrunning clutch. But if I know for sure the engine is gonna have a high idle, then I might relax the high a bit, cuz I hate that harsh engagement into reverse,in the morning as I back out of my stall, with the fast-idle still engaged, and the line-pressure maxed out.