Summit Dual Exhaust Systems

I put summits 2.5 on my 71 duster with hedmen Elites,the only problem I had was with the system was the passinger side exhaust pipe I had to cut as much off the pipe as I could from both ends Must be the style off headers, took that pipe off at least 5 times to make sure it fit right.
Adivce
Messure more than once....