My old pile-of-rust truck Clampy was suffering from Irritable Exhaust Syndrome, not much different from what I myself encounter after a trip to the Super Burrito stand. Unfortunately, the years of northeastern rust had turned Clampy's original Toyota exhaust into paper-thin tubing, and when dragged over rocks it quickly turned into dust. I had done a few haphazard repairs but welding to rust is only a temporary fix, so before the Clampster headed out for more granite crawling I kitted her up with a new Downey stinkpipe and added some features especially for rockcrawling.
Downey is a name that has been synonymous with Toyota parts since before I was new in blue blankie and dirty diaper, and before Clampy was new on some showroom floor in upstate New York. My stories of battered and rusted rattling tailpipes falling off was countered with an invite to try out a ceramic-coated header, stainless steel 2 1/2-inch tailpipes and muffler, a fresh monolithic catalytic converter to keep the smog police at bay, and some flexible couplers to allow a wee bit o' bashing on our next trip out. I didn't have the etiquette to wait for a second invitation and in less than a day had Clampy purring out a new set of tubes. While you check out the specifics, I'm headed for another taco supreme.
This is what I started with: rust, and though the tired four-cylinder in Clampy doesn't put out much power, the little rattle it has was shaking the pipes loose. When combined with rock abuse the old exhaust system was barely hanging on and riddled with hodgepodge repairs. | 
The new Downey ceramic-coated header I bolted on my '86 Toyota four-cylinder is touted by Downey as being a small tube (1 1/2-inch), high-torque system. These heavy 14-gauge units are designed to offer good low-end torque without reducing top-end power (a claimed 7 more ponies at the rear tire), while best of all being California Air Resources Board certified as smog-legal. | 
The header gasket is 30 percent thicker than stock and laced with metal mesh for greater strength. Downey recommends a thick coat of copper-gasket compound for optimum sealing of any grooves and irregularities between the block and header flange. |
The Downey stainless steel muffler is fully baffled, packed with steel wool, and has fully welded end caps with 2 1/2-inch inlets and outlets for best possible flow, resulting in as much of a growl as any four-cylinder can. | 
These stainless steel flexible couplers allow some movement between the exhaust system and the header in case some pointy boulders snake up into the framerails. The Downey exhaust kits are available for '79-'95 pickups and '84-'89 4Runners, and can be clamped together (as I did) or welded in, but remember to read the instructions! The instructions explained that the kit can require some tubes being cut to fit, and a little thought to route everything around suspension and such, but all of this is made clear, so have a seat and read it through first. | |