Without a doubt, today's latest performance parts improve power, driveability, and efficiency over yesterday's factory or aftermarket offerings. to prove our point with regard to the venerable big-block Chevy, we enlisted the help of joey Diorio. His 454-powered '55 Bel air was your typical mid- '80s street/strip buildup. a diehard Chevy man, joey D has been working on small- and big-blocks since the 1960s. His no-jive-five-five (nj55) is a regular street driver that goes to the strip a few times a year and is equipped with a '70s 454/425hp replacement long-block with rectangular port heads. thousands of these replacement motors were sold during the 1970s and 1980s, and we're gonna show you how to make any big-block better.
We chose five key components to update the big-block. By swapping to today's high-tech parts, we knew the '55 could be a better contender on the ever-tougher streets of Jersey. Our first component of choice went right to the heart of the motor: Lunati's latest in camshaft technology, a Voodoo solid street roller. This solid roller stick will offer added lift, vacuum, efficiency, torque, and horsepower over the flat tappet hydraulic it replaces.
For a comparison as fair as possible, we chose a cam with a similar duration, but because it's a roller, the valve will see over .100-inch more lift. The extra lift will dramatically improve street driveability and torque. In the 454 is an old Lunati flat tappet hydraulic with .550-inch lift and 245 @ .050 duration with a 108-degree lobe separation angle. The new Voodoo delivers .655/.663-inch lift and similar 243/249 @ .050 duration with a wider 110 LSA, which should broaden the power curve a bunch.
Before Joey D could try the cam swap, we needed baseline numbers from the Northeast's premier dragstrip (Raceway Park in Englishtown, New Jersey) and dyno digits (SLP Performance Parts in Toms River, New Jersey). E-Town is famous for its great hook, and SLP has a state-of-the-art SuperFlow chassis dyno. Here were the baseline results for e.t. and rear wheel horsepower. At the track on 15-inch Nitto drag radials, the NJ55 went 12.77 at 107.89 mph, while it spun the dyno rollers to 329 hp.
With solid baseline numbers, Joey got busy installing the cam kit (cam, lifters, springs, retainers, roller rockers, pushrods, and timing set) at his home workshop. Initially, the cam was installed with 4 degrees of retard. The retarded cam timing bled off 40 psi of cranking compression (only 135 psi), causing the motor to feel somewhat sluggish. Once the cam was degreed in to the cam card (4 degrees advanced), cranking compression went back up to 175 psi. Before the cam swap the cranking compression was 170 psi in all eight cylinders. Here we definitely illustrated how important it is to degree in the cam.
Once the new stick was properly positioned, the idle vacuum (1,100 rpm) was up 3 inches and we noticed increased throttle response and driveability. Unfortunately, the Rat would consistently start breaking up at 5,100 rpm. With that problem and four more parts to test, we hoped we'd find the solution while dyno testing at SLP. On the dyno, we could closely monitor the air/fuel mixture ratio.
SLP's Director of Engineering Hank Danieki and engineering fabricator Ken Estelle installed a wideband O2 sensor so we could observe the A/F mixture ratio during dyno pulls. On the first couple of pulls we noticed peak torque was up by 60 ft-lb at 4,800 (the same rpm as peak torque with the old cam), but the engine was breaking up at 5,000 rpm and beyond (A/F was 13.8 to 14.0). Even running like a roach, it saw a 28hp gain over the old cam. But it seemed the old 750 Holley wasn't large enough and its metering system couldn't keep up with the new cam's aggressiveness. Still we marched on by stepping up the jetting by six sizes. This added a few ponies but made it way too rich for idling and cruising. At this point we didn't have testing time for another 750 (like a 750 HP) and felt 750 cfm wasn't enough air- flow ingestion for the new combo.
Enter the Holley 950 HP. The 20-something-year-old 750 Holley worked reliably for years with the outdated combination. The new, sophisticated cam needed a modern-day fuel mixer better suited to it. Holley's 950 HP replaced the 750 in a few minutes' time and fired the Rat motor right up. Out of the box and on the first pull we noticed a perfect A/F and no more breaking up-we were stoked! Power was up 20 hp and torque increased 14 ft-lb. Those are big numbers from just a carb swap-and what a difference in throttle response.
Noticing the A/F (13.0 at WOT) was on the money, we didn't need to reach into our boxes of Holley tuning parts (which included, among other items, jets, air bleeds, and squirters). For us, the Holley HP carburetor has proven itself in over 10 years of strip and dyno testing on many different types of motors.
Next, we sandwiched an effective 1-inch, 4-hole tapered spacer from Wilson Manifolds between the intake and the carb. We've found it to be better than an open spacer or no spacer. The tried-and-true Wilson spacer swap netted us another 4 rear wheel horsepower. Excited with another improvement, we just wanted to keep going toward making more horsepower.
Performance Distributors (PD) pioneered the development of the first performance H.E.I. distributor, and we installed PD's D.U.I. (Davis Unified Ignition) distributor and Livewires ignition wires on the '55 prior to any testing. Once we learned of PD's new Mini VIP 18-volt step-up regulator, we wanted to check one out. The Mini VIP works with any 12-volt electronic ignition system that can withstand 18 volts. We plugged in the Mini VIP and realized 7 more horsepower to the wheels. That was a signifi-cant power increase and would easily be worth a tenth at the track.
Weiand claims to have developed the first ever aluminum intake manifold in 1937. In 2005, Weiand began redesigning its manifolds using the latest technology. The new Team G intake, which was released in 2006, would duke it out against its own '70s counterpart. While Smokin' Joe unbolted the old intake, SLP's Estelle fabricated a throttle return spring bracket, then drilled and tapped a vacuum hole for the PCV valve. Next, the newly installed intake was up and spinning the rollers to the tune of an additional 14 hp and 7 ft-lb of torque. That's a sizeable gain considering the old single plane was a well-recognized performer. You just can't beat today's computer-engineered induction. At day's end, the five parts for the No-Jive-Five-Five added up to be worth 73 hp and 87 ft-lb of torque at the tires, which will drastically improve the shoebox's street/strip abilities.
Astounded with the five great bolt-ons, we naturally had to see the effects at the track. For the baseline and strip test we again mounted a pair of Nitto 555 Drag Radials to ensure good bite. We checked the timing to be sure it was the same as when we dyno tested (36 degrees total). With the newfound power the '55 launched harder than ever with a 1.66 60-foot time. The big bad Bel Air boogied through the traps at 11.71 at 113.56 mph-a full second speedier trip down the quarter-mile is like a 125hp shot of juice! A handful of back-to-back 11.7s showed us the consistency of the modern upgrades.
We were impressed way beyond our expectations with these simple bolt-ons. The whole package we tested proved to be an impressive team of power-producing parts. Next time we intend to try out some AFR cylinder heads, so stay tuned.