ordered a Magnaflow system from Troyer and they wanted to know midpipe length for accuracy purposes

i have a 2005 King Ranch Supercrew 4WD. i thought i needed the 16614. anybody know the length of the midpipe from coutside of the clamps?

 

On our 05 Lariat Supercrew 4X4 the midpipe is 24 inches long. The Magnaflow 15821 I have came with 2 different parts, one longer, one shorter. I ended up needing the shorter of the two to install the system.