A couple of months ago, we rolled our '84 Z28 out of mothballs and put it in primer ("Primed and Ready," Mar. '07). This month, lest you think this particular Camaro is destined to be all show and no go, we're adding some go-fast parts to the mix.
You know the score: Third-gen Camaros are very affordable performance platforms. On the other hand, many of these cars--especially the early versions--need a lot of help in the power department. In a nutshell, that's where we're at with our subject. It's a challenging mission, since we're embarking on what many consider a fool's errand: extracting more power from our third-gen's original 305ci powerplant.
Why bother, you may ask. Despite its shortcomings, many of you want to see what we can do with the ugly duckling of Chevrolet's small-block lineup. Truth be told, we want to give it a shot too. These engines ended up in tens of thousands of cars from the mid-'70s through the early '90s. Plain odds dictate that some people will want to use a 305 for their performance build; many others will do it out of necessity, creating an engine piece by piece--sort of like what we're doing here.
Despite our Z28's haggard appearance, we've actually got a decent starting point. Our $1,000 eBay find came with an RPO L69, 190hp H.O. motor made available in '83-86 Camaros. In the performance wasteland that was the '80s, this engine was one of the more potent mills around. Ours was still in good shape. The car's odometer showed just shy of 75,000 miles when we got it, and after our friend Ralph Serrano at D&D Service rebuilt the untouched, computer-controlled Quadrajet, the thing was a decent little runner. Our baseline numbers, recorded on Primedia's Mustang chassis dyno, backed up our hunch. While 158 hp and 181 lb-ft of torque are well south of impressive, let's do the math. The L69 motor came rated at 190 hp at 4,800 rpm, along with 240 lb-ft at 3,200 rpm, both measured at the flywheel. Subtract 20 percent for driveline loss through our 700-R4 tranny, and we're right in the ball park.
That's the good news. The bad news is that our properly functioning, stock L69--fitted with factory-optional 3.73:1 gears and a set of BFGoodrich drag radials--could only propel our Z28 to a 16.59 quarter-mile, with a rip-roaring trap speed of 83.15 mph. OK, we know various magazines reported much faster test times back in the day, when these cars were new. It'd be hypocritical of us to say that you shouldn't believe what you read, so we'll just say that today, in 2007, our example was good for 16s. It was definitely time to get to work. Of course, here in California, we couldn't undertake this project without considering the smog police. We want our Z to be street legal, so it has to be able to pass the test. Put bluntly, our philosophy was this: Anything that can be seen on the car has to be legal for use in Cali and have the necessary EO (executive order) number to prove it. Anything that's not immediately visible, in our book, is fair game--as long as the car passes the sniffer test.
Our first stop was the Primedia Tech Center, where we began our quest for power by upgrading our Camaro's exhaust system with an Edelbrock after-cat system and TES headers, teamed with a Random Technologies Super Stainless catalytic converter. The improved flow provided by this setup netted us some nice power gains, but we also installed the new system in anticipation of what was to come: a set of Trick Flow's Small Chevy cylinder heads. We'll give you more details in the sidebar, but for now we'll point out that these lungs are made especially for 265-305ci engines and, best of all, they're smog legal. Trick Flow also hooked us up with a matching hydraulic flat-tappet cam. It's small, by the standards most of us are used to, but remember we're working with the smallish 3.736-inch 305 bore, and trying to keep the thing smog legal.
In the end, we came up with a real "good news, bad news" scenario. The good news is that our bolt-on barrage netted us gains of 53 hp and 45 lb-ft of torque, which lead to a 1.29-second drop in our quarter-mile time. The bad news is that our Z is still slow. But there's more good news: We haven't yet dialed in our subject's Q-jet to work with the new combo, and we've got some other ideas floating about, so there are certainly more gains to come. These are only the first ingredients added to a little Camaro concoction we're calling The Mulletov Cocktail, and so far, the mix looks good.
Here's the starting point for this project, our Z28's original L69 powerplant, which, at 1
Another original piece still on our car at the outset was the exhaust system, which had ce
Once it was off the car, we intended to cut our old catalytic converter open and check out
A replacement from Random Technology bolted right into place on our car's stock Y-pipe.
The business end of our Edelbrock after-cat system is based on one of the company's SDT (S
We also added a set of Edelbrock's TES headers, done up in the Ti-Tech coating, which Edel
There's no way we can go through everything involved in installing these headers. Given th
That done, the headers slipped into place relatively easily. Bolting the stock equipment b
On the driver side, Edelbrock's directions tell you to disconnect the steering shaft (arro
The TES headers retain the factory heat-riser setup, with the solenoid placed to the rear
Whenever possible, Barron removed the various smog apparatus as a unit. He also made liber
The accessory brackets on the driver side of the engine aptly illustrate the puzzle-ness o
We're obviously skipping ahead quite a bit here, but Barron finally had the top of our Cam
Low miles notwithstanding, our Z28's previous owner wasn't big on changing the thing's oil
Despite its moderate specs, our new Trick Flow Track Heat 'stick is quite a bit healthier
As we pointed out earlier, our subject Camaro actually had its original, nylon-tooth timin
The fact that this build has to be smog legal in California limited our choice of intake m
After thoroughly cleaning the deck surface on our veteran block, Barron and Lee set our ne
With our new heads and intake in place, Barron started putting the puzzle back together. H
TFS' 175cc cylinder heads come with single valvesprings that accommodate up to 0.480 inch
The exhaust ports check in at 67 cc. This is about 85 percent of the size of these heads'
Trick Flow's Small Chevy cylinder heads feature a compact, fast-burn-style combustion cham
The 175cc intake runners are designed to maintain air speed. "The volume is in the bowl so
We've mentioned the incredible array of accessory brackets and smog gizmos mounted on the
With the finish line finally in sight, Lee installed a set of Autolite 3924 plugs and the
|Small Chevy cylinder head airflow |
|(3.766-inch bore) |
|Lift (inch)||intake (cfm)||exhaust (cfm) |
|0.500||242 ||172 |
|Performance Progression |
|181 lb-ft @ 3,750 rpm |
|158 hp @ 5,070 rpm |
|60-ft: 2.47 |
|1/8-mile: 10.63 @ 66.27 mph |
|1/4-mile: 16.59 @ 83.15 mph |
|Add after-cat and cat |
|192 lb-ft @ 3,600 rpm |
|166 hp @ 4,800 rpm |
|Add TES headers |
|198 lb-ft @ 3,700 rpm |
|175 hp @ 4,900 rpm |
|Add Trick Flow heads, cam, Performer intake, K&N filter |
|226 lb-ft @ 4,400 rpm |
|211 hp @ 5,150 rpm |
|60-ft: 2.273 |
|1/8-mile: 9.884 @ 69.61 mph |
|1/4-mile: 15.40 @ 90.53 mph |
|Bolt-on Barrage Shopping List |
|MFG||Part Number||Description |
|ARP||134-3601||head bolts |
|134-2001||intake manifold bolts |
|Edelbrock||5673||Cat-back exhaust system |
|3701||Performer manifold (EGR) |
|68743||TES Headers, Ti-Tech finish Four-bolt flange I-pipe, 3-inch diameter |
|K&N Filters||E-1450||Air filter |
|HP-2002||oil filter |
|MSD Ignition||84111||Extreme Output distributor cap |
|84101||Extreme Output Rotor |
|31459||Super Conductor Wire Set |
|Random Technology||191-30002||catalytic converter, engine code G |
|Trick Flow Specialties||TFS-30300002||23-degree, 175cc Small Chevy Heads w/ 1.47-inch spring upgrade |
|TFS-31400511||3/8-inch stud-mount roller rocker arm set |
|TFS-31478500||Billet timing set |
|TFS-21407850||chrome-moly pushords, 7.850 inches |
|TFS-31400915||engine gasket set, pre `87 |
|TFS-K3140100||SBC cam and lifter kit (hydraulic flat tappet) |