Coyote,
I had a similar time installing mine. I trimed the TVT tubes at each end where the bulge is(was) and then cut both ends of the reduction piece from NW so it was just long enough on each side to firmly hold the clamps. That let me get it closed to the radiator and fit the TVT tubes in snugly. I slid the coupler down onto the TVT tubes and when I had them in place, slide the coupler back up onto the box input. This makes everything much more solid than the factory SL55 tubes and gets even more air back to the TB....

AND you can hear the SC wine better too......