I assume you are using the wide bushing alum.drum.This drum requires the 1971 and up reaction support with the drum oil feed hole modified by grinding the hole between the two seal ring grooves down to the bottom of the hole intersecting it.This will greatly increase the oil volume to the piston chamber area more quickly providing increased holding pressure to the discs.You can see this more clearly explained in Carl Munroe's Torqueflite Transmission Handbook.HPBOOKS-1399 p.164 and 181.