With 1 7/8 you shouldnt have any problems..
you might want to run 1 7/8 but with a 3.5"
collector.. will make more torque.. I'm running
1 7/8 with a 3.5" collector on my 416... It does
go back down to a 3" after the collector but I
also run electric dumps right after the collector
to help reduce back pressure
EDIT
this is with a full exhaust out to the bumper
wave

IMG_20140528_120446433_HDR-w640-h479.jpg
Last edited by MR_P_BODY; 12/08/17 01:17 AM.