1976 Chevy Camaro - Project g/28 Part 7

Ever get the feeling that you're spending a lot of money and going nowhere fast? That's the way we've been feeling lately with our '76 Camaro project car, especially since dropping nearly $7,500 on our smog-legal 383 stroker motor. As the single largest investment in our project car, it was a gamble to let so much ride on a relatively mild motor, but we didn't dare provoke the smog police, hence our decision to go ahead and empty out our wallet.To recap, we had Speed-O-Motive in West Covina, California, build our 383 using proven smog-legal components from the Holley/Lunati/Weiand catalog. On the pump, the modest hydraulic-cammed mill turned out a respectable 403 hp at just 5,300 rpm. We then spent the following month installing the 383 into g/28, painstakingly adhering to all the proper smog hookups, such as EGR, canister purge, PCV, and carburetor heat pipes. We got it running successfully with the stock exhaust system (including the original cast-iron exhaust manifolds and catalytic converter). Needless to say, it felt like a far cry from the 403 hp experienced in Speed-O-Motive's DTS dyno cell. Our fears of massively MIA horsepower were confirmed on the Primedia Tech Center chassis dyno: g/28 made a dismal 177 rear-wheel horsepower at an equally dismal peak of 3,400 rpm.In the real world, we're sure most people wouldn't even fuss with the stock exhaust, but there were three primary reasons for using it in the short term: We needed to get g/28 up and running in a hurry to perform our skidpad and brake testing (see "Back on Track," Sept. '05), and we just hadn't secured the services of a competent exhaust shop. The last concern was the complete lack of emission-legal headers for Second-Generation Camaros. As a '76-model car in California, we would be stuck running the factory manifolds if we couldn't get CARB-legal headers, so we started cold-calling header manufacturers. One by one, we eliminated all the companies until no one was left standing. None of the tech reps at any large header manufacturer admitted to building a legal header for the Second-Generation Camaro--a factory hot rod that was literally built by the millions. As you can imagine, the depth of our despair was only outstripped by our amazement that such an important application could go unaddressed, but we were undeterred. Since we still couldn't believe what we were hearing, we started kicking around on some California government sites, and found the smog-legal master list, the Holy Grail of all 50-state-legal CARB-exempted part numbers.

A Saga: Finding Smog-Legal Parts
In case you weren't aware, the 49 states are required by Federal law to except as legal any aftermarket part that is smog-exempt in California. That's because, in theory, the California law is the toughest. Readers in states with tough inspection standards such as Arizona, Colorado, New Jersey, Connecticut, Missouri, New York, and North Carolina can click on California's Web site (www.arb.ca.gov/msprog/aftermktz /devices/amquery.php) and see a list of every part for every application in every year model and powertrain configuration. There are even pdf files of the actual documentation submitted to the California Air Resources Board by the manufacturer. Beware, the list is extremely long and convoluted (we're talking state-government convoluted here), so plan on digging through it in an hour or more. In a situation like ours when you're at a loss and trying to throw the biggest net possible, the California Web site is the final authority on all things 50-state legal, from blowers and cylinder heads to camshafts and nitrous kits. Every part ever tested and officially validated by the state of California is on this site.

Our tenacity paid off, as we found one sole manufacturer, Hedman, which makes legal headers for '75-80 Camaros: PN 68277 (painted) and PN 66277 (ceramic-coated). What's all the more incredible is that this part is a long-tube 1 5/8-inch header--a far better choice than a shorty or mid-length header.

There is no other company anywhere that makes a smog-legal header for a '75-80 Camaro, so the choice to go with Hedman was not driven by cost, but by necessity. Still, at $231.99 (painted) and $489.99 (coated, both priced from Jeg's), the Hedman's represent a bargain. We opted for the ceramic-coated pipes for better performance, a quicker catalytic converter light-off, and a nicer look. The Hedmans also come with all the doodads you'll need to hook up the smog gear, plus you'll get the all-important sticker that states it's a 50-state-legal part.

Dynomax and The Muffler Man
With headers in hand, we called up our pals at Dynomax for a 3-inch inlet, 3-inch outlet catalytic converter (PN 15147, $139.99). We've used this high-flow catalyst before on a few combinations (a 490hp 396 stroker LT1 and a 650hp blown 5.0 Mustang), so it was a known commodity that could handle our horsepower level without choking things down. The last item we obtained was a 3-inch inlet, 3-inch outlet Ultra Flo race muffler (PN 17221, $67.99). With these pieces, we had the foundation for an easy-to-build high-performance system. All we needed was the right guy to put all the pieces together.

We asked around and everybody told us the best guy for the job was literally right down the street from our office. Lee Watts, otherwise known as The Muffler Man, has his shop on Placentia Ave., a 1/4-mile down the street from us in Placentia, California. Lee builds high-performance race exhausts for a living, and he's damned good at it. Well-honed welding and fabrication skills are part of Lee's success equation, but these are also aided by serious tools, special in-house parts (such as Lee's own bell-mouth Y-pipe used in our system), and a wide selection of mandrel-bent pipe stock. What's more, Lee uses lots of Dynomax products in his customer's race cars, so he was both familiar and comfortable with using them in Project g/28.

Lee began by pulling off our old system and bolting on the new Hedman long-tube headers. This operation was straightforward, unlike the many painful installs we've had with late-model fuel-injected Mustangs and Camaros. Everything cleared the framerails, starter, and steering linkage, but there is a note in the Hedman catalog about the left-side header interfering with close-ratio Saginaw 825 steering boxes. Since we'll be installing the Flaming River gearbox later on, we'll just have to brave it and see if it fits, but in our previous attempt to install the FR box, it appears to take up the same space as our existing box.

We also removed our air conditioning when we installed our Speed-O-Motive 383. Users who opt to keep their stock rotary A/C compressor should note that some modification to the compressor bracket might be necessary, according to Hedman. The final note on the headers is that in order to be smog-legal, you must attach the small heat stove pipe from one of the header primaries to the air cleaner base. This is easily accomplished with Hedman's included kit.

The Hedman long-tube headers terminate with a 2.5-inch collector and ball flange. From that, Lee proceeded to fabricate a 2.5-inch Y-pipe using mandrel-bent stainless steel sections. These join at the Dynomax Super Converter with Lee's own Y-pipe bell section, which takes two 2.5-inch tubes and reduces them to one 3-inch outlet at the converter inlet.

It's worth noting our choice to run a single 3-inch exhaust all the way out. For one thing, anything more than a 3-inch single exhaust is wasted on a 400hp small-block. We've made 500 hp naturally aspirated with a single 3-inch and catalytic converter in the past, so in our experience, a 3-inch exhaust poses no restriction. The second reason is ground clearance. A single 3-incher can be tucked inside the prop shaft tunnel just like the stock 2-inch exhaust, thus saving a few inches clearance at some points. Finally, the extra cost (not to mention weight) of parts for a dual system does not pay dividends in a modestly powered small-block like ours, so why blow the budget? To that end, we spent $1,187.96 on exhaust this month (including the headers, catalytic converter, muffler, raw materials, and Lee's good-guy labor), which is great, considering we only had to point the camera.

From the Dynomax cat, Lee worked his way back using 3-inch stainless mandrel bends. We watched Lee over the next two hours cut, check, tack, tweak, and then weld sections of 3-inch pipe. Like a man possessed, Lee loved his work with such intensity, it was scary--he wouldn't have noticed an earthquake had one struck. We knew we were in the home stretch once Lee welded the Dynomax Ultra Flo in place and put his signature curved side-dump pipe behind the driver-side rear wheel. When we cranked the ignition for the first time, it was like the spirit of another car--a real one--had occupied the body of our jalopy. We savored the smell of light machine oil burning off the pipes while listening to the sharp crackle of the exhaust. Lee Watts, aka The Muffler Man, is indeed the man to call if you need a serious exhaust job in Southern California!

K&N to the Rescue
We pulled onto the boulevard and noticed the difference immediately. As the engine came up through the powerband, we heard and felt the difference right away, but exactly how much difference was there? We wanted to know, so we called up our friends at K&N Engineering in nearby Riverside, California. You've seen K&N's ads where they guarantee dyno-proven horsepower? It turns out K&N can make these claims because it develops all of its products on a chassis dyno, and we wanted in on that action. At K&N we were met by R&D technician Kirk Swanson. Before we tested the K&N air filter assembly we bought from Jeg's (14x3-inch drop base kit, PN 60-1280, $89.99), Kirk made several baseline runs in Third gear using the stock air filter and base (which we modified earlier to accept the four-barrel carb flange). Our power went from 177 hp at 3,400 rpm to 212 hp at 4,400 rpm--an improvement of 35 hp. That's the apples-to-apples comparison of what the exhaust gave us. At that point it was obvious that the stock air filter and base were still blocking some flow, so Kirk pulled those off and put on the K&N drop base, filter, and lid. Voila! Power jumped another 26 hp to 238 hp with a peak of 5,200 rpm.

Followers of Project g/28 remember that our Speed-O-Motive 383 put out 403 hp at 5,300 rpm on the DTS engine dyno, so a direct comparison isn't easy when using a chassis dyno. For starters, SOM tested our smog motor without smog equipment, namely a catalytic converter.

The dyno exhaust was also a 1 3/4-inch header running straight out with no muffler versus our more restrictive setup. Plus, the SOM dyno test used an electric water pump with no drive accessories like alternator, fan or power steering attached. We had all four sources of parasitic drag running (fan, power steering, alternator and water pump) on the chassis dyno. If we pull out a conservative 15 percent drivetrain loss for our TCI Turbo 350 trans and TCI BreakAway torque converter, that leaves us with roughly 340 horsepower at the wheels. Subtract out another 20 or 30 hp for the catalytic converter, fan, water pump, alternator and power steering, and we're hovering in the area just north of 300 rear-wheel horsepower. For everything to pencil out, we need to be looking at around 310 rear-wheel horsepower. That being the case, it looks like we're actually short by about 70 hp.

For one thing, we know we're not going to get into the 12s with just 238 hp at the wheels. Gears, slicks, and other mojo tricks will only take us so far: we need that missing power! Where'd it go? The answer could be lurking in a number of areas like ignition timing, vacuum advance, jetting or partially opening vacuum secondaries. We'll soon be going over things with a fine-toothed comb using the chassis dyno as a tuning tool. We also have to install our Detroit Locker TrueTrac differential and Randy's Ring & Pinion 3.73 gears, so check in with us next month to see what happens.

Lee Watts of The Muffler Man...        read full caption Lee Watts of The Muffler Man in Placentia, CA, examines some of our components before putting them on. Note that there were several Dynomax mufflers to choose from. Because the system on our '76 Camaro project car was fabricated by Lee from scratch, we had no idea which muffler would be best.

Lee Watts of The Muffler Man...        read full caption Lee Watts of The Muffler Man in Placentia, CA, examines some of our components before putting them on. Note that there were several Dynomax mufflers to choose from. Because the system on our '76 Camaro project car was fabricated by Lee from scratch, we had no idea which muffler would be best.

Take a close look at these...        read full caption Take a close look at these ceramic-coated 1 5/8-inch long-tube headers from Hedman-they're the only headers on the market that are smog-legal (under California Air Resources Board exemption order No. D-176-27) for '75-80 Camaros. The quality is quite good on our set, which costs $489.99 from Jeg's. Gaskets, fasteners, and smog hookups were included as well.

Lee Watts (aka The Muffler...        read full caption Lee Watts (aka The Muffler Man) is an artist at what he does. Whether he's working on a junk Camaro like ours or a high-end race car, his work is always top-shelf. Note the many subtle bends Lee used for our system-all of them to maximize the available space. No shortcuts were taken and we got a great price on the work too.

We settled on one of Dynomax's...        read full caption We settled on one of Dynomax's Ultra Flo race mufflers (PN 17221, $67.99), which is built like a tank and has a great sound. The single 3-inch inlet/outlet of this muffler has the simplicity we were looking for. Its 14-inch length also was the best fit for our tight OEM placement.

You can easily see where the...        read full caption You can easily see where the two 2.5-inch mandrel-bent pipes from the header collectors merge into the Y-pipe before the catalytic converter. The Muffler Man makes its own Y-pipe bells for situations just like ours. (You can call Lee at (714) 524-7818 to buy one for your own system. They run about $20.) The outlet side of the Y-pipe bell is 3 inches, which matches our 3-inch Dynomax Super Converter perfectly. From the catalytic converter outlet, it's 3 inches (stainless, mandrel-bent) all the way out.

Under the hood on the driver's...        read full caption Under the hood on the driver's side, you can see how much clearance is afforded by the Hedman headers. Camaros with air conditioning may need some modifications to the A/C bracket for clearance on this side.

This little thingy on the...        read full caption This little thingy on the passenger-side header is the heat stove pipe, which is required for emissions. For our smog tests we plan to run the stock air cleaner base and this flex pipe to pass the visual exam. For racing (off-road, of course) we'll take the hose off and use a K&N 14x3-inch drop base and filter, which is much less restrictive.

Here's the view of the finished...        read full caption Here's the view of the finished system from the rear of the car showing the excellent work of Lee Watts.

We wondered how Lee was going...        read full caption We wondered how Lee was going to fabricate the Y-pipe while using long-tube headers and retaining the catalytic converter. The result is elegant and functional, and retains good access to all the key parts of the drivetrain.

In the rear, you can see how...        read full caption In the rear, you can see how nicely the Dynomax Ultra Flo muffler fits in this application. Note Lee's signature exhaust dump in front of the rear driver-side tire. It sounds a good as it looks, too.

We thought the Hedman headers...        read full caption We thought the Hedman headers could've run closer to the floor, but we guess it's better to be safe than sorry. At its lowest point, there was still about 4 inches of ground clearance. Tight, but workable.

Here's the pile of crap we...        read full caption Here's the pile of crap we took off Project g/28. It's amazing our 383 made 177 hp with this junk hooked up.

It's far from pretty, but...        read full caption It's far from pretty, but here's the way the engine looked for our baseline dyno test (after the new exhaust, before the K&N filter). With the stock filter, filter base, and lid (i.e. smog-legal street trim), the Speed-O-Motive 383 cranked out 212 hp at the rear wheels on K&N's Dynojet chassis dyno (at 4,400 rpm peak).

Kirk Swanson of K&N then swapped...        read full caption Kirk Swanson of K&N then swapped the stock filter and lid for the K&N 14x3 filter and drop base...

...The K&N kit (filter, base,...        read full caption ...The K&N kit (filter, base, lid, threaded rod, bolt, and washers) clears the stock hood of our '76 Camaro without modifications and cost us $89.99 from Jeg's.

This before/after horsepower...        read full caption This before/after horsepower graph shows Project g/28 after The Muffler Man exhaust and Hedman header install. The comparison is with the stock filter, and then with the K&N filter kit. With the stock filter, g/28 made 212 rear-wheel hp at 4,400 rpm. With the K&N kit, it picked up 26 hp (for 238 hp at 5,200 rpm). The graph at the bottom shows the air-fuel ratio from the wide-band sensor placed in the exhaust. Note how the K&N filter (red trace) admitted more air into the engine, thus leaning it out by about half a point.