I'm considering building an inexpensive single stack for the truck. Aside from the stack itself, do I just need a 4" 90*, enough pipe to get it through the bed and then the adapter to get it from 4" to whatever the stack size is? What is the need for flex pipe?

Thanks

 

Since the stack is bolted to the body (bed) of the truck and the rest of the exhaust is attached to the frame there will be some movement. The flex pipe allows for this movement so you don't crack or completely pull your exhaust apart...

 

run flexpipe up to the bed if ur cheap, then you'll have to get an adapter from 3-5 or 4-5 whatever you stock size is and all stacks are pretty much 5" at the bottom,i would run a 5" 90 bend in the bed to the stack

 

although at some point you do need a small section of flex pipe so you dont break your system, but ive seen people only use flex, you'llneed the mount for the front of the bedrail

 

http://store.airflo.com/exhaust-tubing.html

 

This is everything that my exhaust system entails. including the down pipe. I used the 2 short radius 90s to kick the stack over closer to the bedrail. but it makes it sit higher than I like. so I'm going to use only the long radius 90 and lower the stack some. you use band clamps for flexpipe to hardpipe connections. some are stepped some are flat clamps. depends on what you need. mine is 5" id flex and 5" od hardpipe. so I slide the flex onto the tubing and use a stepped band clamp

 

I prefer the stepped band clamps myself as the flat ones always seem to leak where they bolt together.

 

ya the stepped clamps are pretty good at sealing up.