Straights on NTC 400 Big Cam

All depends what u want, im a bit of a tight wad so i went with 6's and it reduces to 5 at the bottom, thru big rig chrome shop they were bout $380 a piece. I didnt want to spend another 600 for elbows. 6 into 5 isnt very noticable anyway and my stock elbows come out above frame i didnt want to mess with all that under the cab no room to work

 

Ideally go 6 right from the turbo but the best you'll probably find is from the y pipe. The problem you'll have is that the pipe goes above the frame and below the floor so space will be at a premium. Make sure you leave room for a resonator because you'll be putting one on shortly. Those old Cummins are loud especially on the Jake.

 

84" tall 6" miter cuts that are reduced to 5" at the bottom are around $215 a piece from 4 states. I run a set of these on my cabover, it's not too loud even for long periods of time, might be different if they were beside the doors.