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Small Block Bolt Ons - Bolt-On Barrage

Can we give a 305 small-block some muscle? We aim to find out with a...

John Nelson May 31, 2007

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 190 hp, was the most powerful engine available in an '84 Camaro. That's obviously not powerful enough for our purposes. On the other hand, it's only got 75,000 miles on it, as evidenced by the 140-psi cranking-compression-test readings and the fact that its original, nylon-tooth timing chain was still in place.

Another original piece still on our car at the outset was the exhaust system, which had certainly seen better days.

Once it was off the car, we intended to cut our old catalytic converter open and check out its innards, since we'd gotten the thing red-hot during our baseline track testing. No need--the catalyst material poured out in chunks. Primedia Tech Center Manager Jason Scudellari's comment: "Hey, that's what I heard hitting the wall behind the dyno!"

A replacement from Random Technology bolted right into place on our car's stock Y-pipe. This ensured that it would also bolt right up to the flange on our Edelbrock TES header setup, designed specifically for '83-86 H.O. Camaros. At the other end, however, the cat didn't match up to our after-cat system. Edelbrock provided a matching flange (arrow) and a new 3-inch intermediate pipe. The flange was an exact fit on our new cat, but the I-pipe required some modification; Scudellari handled the cut-and-weld with no problem. The flange and pipe are available from Edelbrock if you want to go with this route; otherwise, you'll need a set of "standard" headers and a catalytic converter to match.

The business end of our Edelbrock after-cat system is based on one of the company's SDT (Sound Deflection Technology) chambered mufflers, which is finished with Ti-Tech coating, same as our headers, for durability. The dual 2.5-inch outlets feature polished stainless, slash-cut tips. We picked up 8 hp and 11 lb-ft, along with a deeper, much more aggressive exhaust note.

We also added a set of Edelbrock's TES headers, done up in the Ti-Tech coating, which Edelbrock says becomes tougher with repeated heat cycling. TES headers are designed to accept all necessary smog equipment; note the air injection fittings (arrows), which make hooking up the factory A.I.R. tubes relatively easy.

There's no way we can go through everything involved in installing these headers. Given the Byzantine array of smog hoses and accessory brackets, all we can say is take lots of pictures (we did) and keep a factory shop manual on hand. One thing we should point out is that you'll need to remove the passenger-side heat shield to get the headers into place.

That done, the headers slipped into place relatively easily. Bolting the stock equipment back into place calls for a little improvisation. The air injection fitting is in a slightly different place than stock (arrows). Longer lengths of heater hose easily bridge the gap.

On the driver side, Edelbrock's directions tell you to disconnect the steering shaft (arrow) before installing the headers. You're not going to want to do it, but it is necessary.

The TES headers retain the factory heat-riser setup, with the solenoid placed to the rear of the pipe instead of facing forward. The small tube that runs to this piece will need a bit of massaging to work with the new arrangement. It would be a good idea to mount a new piece of fuel line on the riser before bolting it into place... Trust us on that one.

Whenever possible, Barron removed the various smog apparatus as a unit. He also made liberal use of a digital camera to keep track of where everything went. "This thing is a big puzzle," was our man's assessment of the situation. It helped that the proprietor of Don Lee Auto Service, Tim Lee, had been around the block a time or two with the '82 Z28 he owned back in the good ol' days.

The accessory brackets on the driver side of the engine aptly illustrate the puzzle-ness of the Camaro's belt setup. Here, Barron has loosened the power-steering pump from one of its fastening studs so that one of the interlinked A/C compressor brackets can be pivoted out of the way. Again, we have to emphasize the importance of taking pictures and keeping track of how all this stuff goes together.

We're obviously skipping ahead quite a bit here, but Barron finally had the top of our Camaro's 305 stripped. Stock combustion chambers nominally measure 58 cc, but Trick Flow's Artie Kakiou says he's seen them vary between 54 and 60 cc. Other than that, there's not much to say about the iron L69 heads except that they're heavy when you have to yank them out of an engine bay.

Low miles notwithstanding, our Z28's previous owner wasn't big on changing the thing's oil, as evidenced by the sludge in the engine valley. The original lifters had mushroomed, making extraction difficult. Barron had already removed the Camaro's radiator and A/C condenser, so we were ready to pull the stock cam, which came out with more than one flattened lobe.

Despite its moderate specs, our new Trick Flow Track Heat 'stick is quite a bit healthier than the factory broomstick cam it replaced. With 1.6:1 rockers, lift comes in at 0.469/0.484 inch intake/exhaust, while duration measures 210/216 degrees at 0.050 inch. LSA is 110 degrees. Chosen in consultation with Trick Flow's Kakiou, the idea was to maintain good idle quality and vacuum--and to allow the car to pass an emissions test. Though not particularly radical, this cam did endow our Z with a nice, rumbly idle.

As we pointed out earlier, our subject Camaro actually had its original, nylon-tooth timing chain in place when we took it apart. Trick Flow sent along a billet-steel true roller timing set to replace it. While we had the timing cover off, we went ahead and pulled the oil pan, installed a new oil pump, and replaced the leaking oil-pan gasket.


Random Technology
Loganville, GA 30052
Trick Flow Specialties
Tallmadge, OH 44278
Don Lee Auto Service
D&D Service
Hawthorne, CA

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