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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...
May 31, 2007
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Small Block Bolt Ons - Bolt-On Barrage
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.
The fact that this build has to be smog legal in California limited our choice of intake manifolds. We picked up an Edelbrock Performer, PN 3701, which incorporates provisions for the factory EGR valve. Bolted in place with ARP intake bolts, the Performer sits just a bit higher than the stock piece, but everything just fit under the hood.
After thoroughly cleaning the deck surface on our veteran block, Barron and Lee set our new Trick Flow lungs in place and torqued them down with ARP head bolts. Trick Flow also provided a full gasket set, one-piece chrome-moly pushrods, a pushrod-length checking tool (which we didn't need, since the ones they sent were right on), and a set of 1.6:1 roller rocker arms.
With our new heads and intake in place, Barron started putting the puzzle back together. Here, he's reinstalling something else we need to stay smog legal, namely our Camaro's smog pump. While we had the front of the Z's engine apart, we went ahead and installed one of Edelbrock's Victor-series high-flow water pumps. It took a bit of effort to get the stock bracketry to fit around it, but we consider the improvement in cooling ability worth it.
TFS' 175cc cylinder heads come with single valvesprings that accommodate up to 0.480 inch lift. We went for the optional 1.470-inch single-spring setup, which can handle up to 0.540 inch valve lift; the dual-spring version works with lift figures up to 0.600 inch.
The exhaust ports check in at 67 cc. This is about 85 percent of the size of these heads' 1.50-inch exhaust valve, which is right where it should be, according to Kakiou.
Trick Flow's Small Chevy cylinder heads feature a compact, fast-burn-style combustion chamber that measures 56 cc. "It's designed to be an efficient chamber design," says TFS's Kakiou.
The 175cc intake runners are designed to maintain air speed. "The volume is in the bowl so the cross-sectional area can be smaller for better velocity," says Kakiou. Keeping the intake velocity helps any motor, but especially our small-bore 305, build more torque.
We've mentioned the incredible array of accessory brackets and smog gizmos mounted on the front of our Z's engine. In the home stretch, we found that the tall valve covers Trick Flow sent wouldn't fit beneath all the stuff that needed to be mounted on, over, and around this area. We'll eventually switch to one of Fel Pro's extra-thick 1604 valve cover gaskets, but for now, we glued two regular gaskets together and installed them under the factory valve covers.
With the finish line finally in sight, Lee installed a set of Autolite 3924 plugs and the MSD cap, rotor, and wires we happened to have on hand, and prepared to fire her up. To make sure our new hydraulic flat-tappet cam got a proper break-in, we ran Delo 400 diesel oil for the first 20 minutes then switched to normal 10W30 lube. K&N supplied oil and air filters, Lee reset our timing, and we were off to the street-legal drags before our date with the dyno.
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