Need some help... new TTI exhaust wont fit

Need a little help. Not sure what is going on but my new TTI exhaust will not fit. Bought the 67-76 A body 2.5” full exhaust with H pipe. This is coupling to their small block shorty headers and extension pipes. My first issue is the intermediate H pipes run into the floor.... not good... and then the second issue is the muffler hanger clamp that bolts to the seat belt bolt is the wrong angle and not far enough back. If I place it on the pipe and hold it up it would be perfect if there was a hole on the floor on the move vertical wall of the floor...

this car 1972 Duster has had quarters repaired but could there be something else going on....

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