Car guys have always had to battle the public stigma of driving their works-in-progess. It's the beauty is in the eye thing, except that no one applies that rationality to a guy and his project car, or truck in this case.
The only guys that society seems to tolerates driving a 15-foot long contractor-white 80's F150 are landscapers, city workers, and appliance haulers. Anyone else piloting this square heap will attract contemptuous looks and nasty glares. So you just have to let it slide off your back and press on with whatever appeals to your senses. This is precisely why we're upgrading the exhaust system on the Big & Ugly Work truck. We're out to appeal to our auditory senses with a set of headers and Flow's. It's the perfect modification to projects like this - because we know the resultant rumble and roar will make us impervious to societies stares and glares.

DIY Exhaust

The biggest restrictions are between the manifolds and the first catalytic converter.

You'd think that with a 5.0L powerplant the '87-'96 F150 should sound like a Mustang. Unfortunately about all it shares in common with the Fox body Mustang exhaust system is the restrictive cast iron manifolds. From there the F150 plumbing routes both banks into a pre-catalytic converter. From here it goes into a short 3-inch pipe leading to the second converter. The gasses are then squeezed out through a 2-1/4" single tube and into big cylindrical muffler before wheezing it out a limp tailpipe behind the right wheel.

If we weren't restricted by California's illogical smog laws we'd put in a true dual exhaust system. A set of headers followed by an H or X pipe, and then a pair of mufflers. We'd even run a pair of high-flow catalytic converters and we know it would pass with flying colors. However the state bureaucrats won't allow for the factory exhaust configuration to be changed.

A set of shorty headers will pave the way for an eventual head upgrade.

Since our hands are tied we opted for the best we could. We picked up Flowmaster's "cat back" exhaust kit for this era of F150. It features their 50-series SUV/Truck muffler in a single-in and dual-out configuration. We've also opened things up with a pair of Flowtech shorty headers. Without tackling the restrictive catalytic converter section we're not expecting any significant power increases. However it's just a beater truck and the exhaust note quality is what we are really after for now. Listen to the before and after (side bar) and you'll see what we mean.

Can Flowmaster's clamp-together muffler kit go together straight and leak free? We're about to find out.

The Flowmaster kit is meant to be a DIY kit. It comes complete with clamps, brackets, and tubing engineered to fit any of the F150 cab and bed lengths. Clamp together exhaust systems tend to get a bad rap. They often leak and sag, leading the owner to inevitably pay an exhaust shop to weld it together. We wanted to see if a guy could really install this himself without the need to weld up pipes. Greg Coons of Greg's Mufflers and General Automotive Repair, in Lafayette CA, offered to show us how to properly install a clamp together kit. He offered up plenty of tips to make the kit look like a professionally installed job, leak and sag free.

We drove the F150 over to Greg's Mufflers in Lafayette, California. Greg's has been serving the East Bay for over 30 years and has one of the largest Flowmaster stocks around.

We asked Greg to attempt to install this kit as a regular guy would in his driveway. He did exactly what one of us would, which is to throw the supplied instructions to the side. "We don't need no stinkin' instruction manual."

The first tip - soak all the rubber exhaust mounts in WD40. You'll go nuts fighting them dry and they'll either win or self destruct. Let 'em soak and the hangers will slide right out.

The task begins with cutting out the stock muffler and exhaust piping just to the second catalytic converter. Greg uses a torch, but an Sawzall or hacksaw would accomplish the same.

The factory muffler uses a single 2-1/4" inlet and outlet. We presume the inside of the muffler consists of a perforated tube and fiberglass sound deadening material. Whatever, its headed to the scrap heap.

Since we're in California we have to keep the converters in place. This means using the supplied transition pipe, which takes the 2-1/4" converter outlet and steps it up to 2-1/2". Slip it on ensuring the button on the converter pipe lines up with the notch in the tube (see arrow.) A supplied 2-1/2" clamp is positioned right against the button.

The kit includes a oversized intermediate pipe. Unless you have the crew-cab and 8' bed this pipe will surely need to be cut to length. Greg shows us how to do this properly so that you don't cut too short and end up with out of whack muffler and tip alignment. First slip the pipe completely onto the converter transition pipe.

Temporarily install the passanger side tail pipe. It routes over the axle housing and slips into the existing factory hanger.

(Exhaust Installation continued)

In This Article:
We continue to modify the Big & Ugly Work Truck. This time we're addressing the restrictive single exhaust system. The truck receives a set of Flowtech shorty headers and a Flowmaster exhaust kit. Greg's Mufflers of Lafayette, California gives us tips on how to install a clamp-together exhaust kit without leaks.

The unsightly 1988 F150 will at least sound better with the aid of Flowmaster's "cat-back" exhaust kit. This is part number 17221, with tips exiting at the bumper. Part 17239 puts the tips behind the wheels. Both kits fit '87-'96 F150 trucks, any wheelbase, 2 or 4 wheel drive. Street prices are about $320.
The truck doesn't deserve a pair of headers that look this nice. These are Flowtech shorties, 50 state legal, for '87-'96 F150 and Bronco (PN 91627 for 5.0L and 91628 for 5.8L). Not likely to do much for power right now, but once we swap the stock heads for a better breathing set, they will really shine.
  Hear it!
Stock Exhaust

With Flowmasters


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