Dumped the pics off my phone and found something that might make useful tech for someone on here. If you want to replace an old rusted exhaust system, or you want a better-flowing setup but without the "performance" muffler noise driving you nuts, or you're just a cheap bastard like me, check it out.

A replacement tailpipe muffler assembly for a V6 truck is virtually identical in shape to the 4-cyl. but is 2" instead of 1.75, an increase of 29% in cross section. I paid about $70 delivered for this unit from Bosal:


A replacement cat for a V6 truck is also 2" and has the proper flanges on it. I paid $95 for mine.

If you have a later EFI truck and don't do deal with the price and annoyance of a header, hit the yards and find an older carbed truck with the twin-downpipe on it. It flows much better and isn't susceptible to weld failure at the neck like the crap EFI-style pipe. It also dumps out at 2" if you whack it off right before the cat. I got mine free with a spare manifold I bought off of craigslist.

Install the downpipe on your manifold and bolt the downpipe clamp onto the bellhousing. Bolt the cat onto the catback, bolt a universal 2-bolt flange onto the other end of the cat, then hang the entire assembly under the truck in the stock hangers. Using some scrap 2" pipe, weld the downpipe to the flange and you're good to go.

The whole thing took a couple hours of chasing parts, about an hour fitting, grinding, and welding, and cost me about $175. If you're running catless it will cost you considerably less.

If you are in California this probably won't pass visual, but if all you need to pass is a sniffer test then you're good. No dyno result, but seat of the pants feel is much improved vs. the bone stock setup, especially at low to midrange RPM.

If you're nervous about the muffler being cheap and rusting out or blowing out, I will tell you that I drive like a maniac and ran it all winter with liquid de-icer everywhere and it's still shiny and quiet.

I haven't tested it, but I have measured one and I believe this will work on a second-gen truck as well.

 

That's a pretty good idea for a cheap exhaust upgrade! I never knew the v6 version of those is identical just larger diameter.

I think it might pass CA emissions as long as the o2 sensors are in place and the EO# for the CAT matches the engine type. The rest I don't think matters, it would look somewhat factory otherwise

 

O2 sensors are easy to do with this setup. When I converted to the twin-tube downpipe I moved the front O2 sensor up into the manifold where it would have been on a feedback carb truck. All the manifolds have a boss for the sensor, and the cast material is easy to drill and tap. Alternately you can just put a carb manifold on your truck and your EFI sensor will bolt right in. My truck is an RE-C, so I converted my rear sensor to a screw-in Ford unit and just welded a universal bung into the back of the cat. It works great, no codes or issues at all.

Two other things I forgot last night:

If you have a shortbed truck like mine you will need to cut the midpipe support bracket off your old exhaust and weld it onto the new pipe. The V6 unit has that bracket on the midpipe to the cat, but you won't be using that part on a shortbed.

Also, be careful how close you tuck the cat to the truck. I went out of my way to tuck it very tight and then found it rattled on the crossmember a bit on hard accel due to worn motor mounts. A quick clearance of the flange solved it, but better fab work would have saved me the trouble.