my truck recently took a diet and i cut the 5" exhaust off about were a stack would bend to go up in the bed. I have purchased a 5" ID/OD custom bent elbow to put on and then a tip may or may not go on that. I would have gone further back but I have traction bars and they are in the way.

before I weld the elbow section on I want to drive it a bit and get to know what sound I prefer with the elbow end and direction its facing. I know facing down to the ground is going to be loudest. so what is going to be the best to clamp this section on without it heating and expanding and falling off the truck while i drive. again this is a 5" pipe mating with a 5" ID/OD custom elbow.
Saddle clamp?

if anyone close to Souther Oregon want my 5" exhaust that i cut off its yours for free

 

Get a exhaust band clamp, any HD truck parts place will have them. They hold great and let you take the exhaust apart again if you need to.
Looks like this: