Not sure, but I would say the aftermarket Y-Pipes are designed to fit ALL transmission options. The T-19 and C-6 are smaller than the later ZF-5 and E4OD's. For example, the early turbo kits were transmission specific. The later ones were designed as a "one size fits all", so from the stock one on a 6.9 would probably look different than the aftermarket one. The aftermarket one I would guess would be a bit "taller" from the connection to the manifolds to the junction that makes the Y so it can reach all the way around the bell housing on the E4OD and ZF-5..... they bells on those 2 are significantly larger. I know even with the one size fits all design, on at least one of the turbo kits, there is an "ear" that you have to cut off the back of the E4OD bell for the kit to fit.......
