I just built a 4" cat-back (no muffler) for $155 in about 2 hours. requires cutting and 3 or 4 easy welds.

Parts list/shopping list at the diesel truck shop:
1--4 inch 45* mandrel bend (one expanded end) $33.xx
2--4 inch 90* mandrel bends (close radius, one epanded end) $33.xx
5 or 6ft--4" pipe (6.xx per foot)
3--4"exhaust clamps ($4 each)

the intermediate pipe (I-pipe):
-use the 45* bend to adapt to your cat
-slip/clamp 30 inches of 4" pipe from the 45* bend along the driveshaft
-make a 60* bend by cutting one of the 90* bends
-weld a 6-8 inch pipe to the cut end of the 60* bend
-slip/clamp the 60* bend over the I-pipe in front of the rear
-slip/clamp the other 90* onto the 60* over the axle.


no muffler:
-use the scrap (30* bend) from making the 60* to weld to the 90*bend after the rear, over the panhard bar. this works because two 90s makes 180... aka a straight line out the back.
-weld a 24-30" piece of 4" pipe to the 30* bend for your tailpipe

If you gotta have a muffler:
-buy another 90* bend
-weld a 8" pipe to the 90* over the panhard bar.
-slip/clamp a 90* bend over the 8" pipe and attach your muffler to that
-(tailpipes depend on your muffler)

-reuse or get a new hanger for just after the rear to hold your muffler or tail pipe.

 

Nice work man! Any pics?

 

+1. Might be work for the 383.....good post!

 

I forgot to take a picture of the over-axle and tailpipe, but its not that difficult to imagine a 90 to a 30 to a straight piece out the back

 

Are you saying that expensive Y isnt worth it?

 

not sure I understand your question.

It cost me $60 in mandrel U-bends, $85 each for the converters, and prolly like $30-$40 of welding materials/argon. Not to forget way too much time and effort! but it is 3" pipe and the cats are getting cut off by next week... pending a wastegate test.