1984 Chevy Camaro - Power Struggle

This Q-jet is rated to flow 750 cfm, just like its analog brethren, but you've gotta achieve wide-open throttle to get all that flow. Believe it or not, failure to achieve WOT is common. "It amazes me how many times I see it," Murphy tells us. The butterflies will actually be at a slight angle, as shown, when the carb is open all the way.

On the scene for our Z28 dyno session, Murphy first took a crack at making our freshly rebuilt but utterly stock carb work. We outfitted our Z with an O2 sensor bung for the occasion, taking advantage of the ability to check our air/fuel ratios at various rpm. After adjusting the air valve tension to get the doors to open a bit sooner, he swapped out DR rods for a set of leaner DP pieces.

We didn't achieve our highest power levels with this combo, but the simple changes made a huge difference in our Camaro's powerband, eliminating the midrange drop-off we'd been cursing at the dragstrip.

Not surprisingly, our best results occurred with the mixer Murphy built us sitting atop our much-abused 305. We started with a pair of CG secondary rods in place, but leaner was the order of the day. Murphy started by turning our mixture control solenoid down 1.25 turns, made a 1.5-turn adjustment to the idle air bypass circuit, then went from CG to CZ metering rods, "the leanest made," we were told. Removing the spark arresting ring from our air cleaner increased airflow, so we switched back to DR rods.

We called on GMCOPO to help us deal with the computer part of our computer-controlled equation. The chip we received has a high-performance spark curve, an improved carburetor duty cycle, and revised toque converter lockup specs. Also sent along was an '87 G-body-spec ECM. We included a 180-degree thermostat and a lower-temp fan switch. GM doesn't service the part anymore-pick up a switch for a Grand National and you'll be OK.

As part of our power-tune regimen, we sought a hotter spark by adding one of Performance Distributors' computer-controlled distributors. It features a 50,000-watt coil and a hi-po seven-pin module with increased dwell time to saturate the coil. We added a set of low-resistance LiveWires. They come wrapped in a heat-resistant sleeving, and for a car we call the Mulletov Cocktail, we couldn't resist getting them in camouflage.