Those of us who have modified our cars for more performance for two or three decades know that in some respects the "good old days" really weren't all that good. There were some great aspects: cruising was actually semi-respectable, an occasional street race wasn't regarded as a grossly antisocial act, old Chevys were inexpensive and easy to work on, and 100-octane gas cost less than half a buck a gallon!
There weren't smog laws to worry about, but a lot of the modifications made in the name of more power made our cars run slower, use more gas, and occasionally ruined their driveability. A big part of the problem was that not many people really had a clue as to what worked and what didn't. If, for instance, you were fortunate enough to own a '61 Corvette with the base 230hp engine and you wanted to pump up the power output, you could be pretty sure that by utilizing the factory dual-quad intake and carburetors, and factory 270-horse cam, you'd end up with something roughly equivalent to a 270-horse 283. That was because you were, for the most part, re-creating a higher horsepower, factory-engineered package.
On the other hand, if you bought parts from the local speed merchant, the process was kind of like going to a Chinese restaurant and ordering one item from column A, two from column B, and one from column C; sometimes the combo tasted great, and sometimes it wasn't fit to eat. Using our hypothetical '61 Corvette with the 230-horse engine, you might luck out with a combination of parts, usually from a number of different manufacturers, that actually improved the old 283's performance. You could just as easily wind up spending a lot of your hard-earned dollars to get a setup that was an over-carbed and over-cammed, barely driveable eight-cylinder disaster that guzzled gas like a wino on cheap port, and couldn't outrun a six-cylinder '55 Ford.
The problem was an assemblage of parts that wouldn't-or couldn't-work together harmoniously. It could be caused by either the buyer or seller's pure ignorance-or both. Maybe the blame could be pinned only on the speed shop owner's greed; sell the customer the most expensive parts available, and who cares if the end result works. Lots of speed shop customers believed the old adage that if a little was good, more had to be better, and a whole lot would be just about perfect. Thinking along the lines of, "If a 230-horse 283 uses one four-barrel and a 270-horse has two small 'fours' on a low-rise manifold, then I'm gonna get a lot more power if I slap two big fours on a tunnel ram." Or, "A Duntov cam has more lift and duration than the 230-horse engine's cam, so if I get a cam with gazillion degrees of duration and a couple feet of lift, I'm gonna get way more power than with the Duntov." Yeah, right!
That's not to say that the individual parts were no good; they just weren't right together. The key to a good-running modified engine is the right blend or combination of components-not a random selection of items that may not work well together.
One of the greatest performance developments in recent years is the engineered performance packages that eliminate the old "by guess or by golly" approach to buying high-performance parts for your classic Bow-Tie. Engineered packages are the result of a manufacturer designing and testing cams, intake manifolds, even cylinder heads to work together as optimized assemblies. These "packages" may be listed as individual components that are engineered to work well together or as an essentially complete system that can be ordered under a single part number. Best of all, many of these are 50-state smog legal. If aftermarket performance parts can get the blessing of the California Air Resources Board, they have to be good, at least from the environmental standpoint. And for said aftermarket performance parts to be environmentally friendly enough to satisfy the Golden State's clean air cops, you can bet they've been carefully and well engineered.
The best way to describe a performance engine system is as a total air and fuel management system. Cylinder heads, intake manifold, and camshaft are all designed and engineered to work well together. The heads are crafted to optimize the airflow ratios between the intake and exhaust runners, and airflow characteristics of the heads and intake are matched as closely as possible. A camshaft is configured so its lift and duration work harmoniously with the heads and intake to provide a powerband that's appropriate for the intended use of the system. A well-engineered street system should return better gas mileage (assuming the driver can keep from slamming the pedal to the floorboards too often) than stock.
In the March '98 issue of Super Chevy, my son Rob outlined what went into resurrecting a '73 El Camino that had been in the family since new. Teenagers can be fickle at times. Rob had wanted the 93,000-mile original Elky, then, after we got it in tiptop running order, decided he'd rather have a car with a blue oval badge. His loss, my gain.
"Smog" cars from the '70s are slugs; low horsepower, poor driveability, and miserable fuel economy. The El Camino was typical of the era, with an emasculated 145hp 350 that inhaled through a two-throat carb and dumped its exhaust out of a single 2-inch pipe and muffler. Adequate is the kindest thing I could say about its performance and, as much as I like the old beast, it wasn't much fun to drive. It definitely needed more power.
After studying what was available to pump up the trusty 350's power output while keeping it reliable and street-worthy, I found there were two major manufacturers offering complete, integrated systems. Both are highly reputable and renown for topflight engineering and quality products. Both companies' systems offer relatively comparable performance gains, and there's not a lot of difference in their pricing. Ultimately, I opted to go with one of Edelbrock's Total Power Package Systems for Chevy small-blocks.
Edelbrock has four distinct power packages for small-blocks, each a group of parts matched for a specific level of performance in a desired rpm range. One, the "Performer Power Package," is engineered for a broad, streetable powerband with more grunt from right off idle to 5,500 rpm. The other three are progressively less streetable and more oriented to high-rpm horsepower. Most of its applications are 50-state smog legal, which is important in a lot of regions. All I wanted out of the '73 Camino was more grunt for the street, so the basic Performer Power Package was my choice.
Depending on the specific year of the car and engine, there are several variations of components in the Performer Power Package. The appropriate components for the '73 start with a pair of Performer aluminum cylinder head assemblies (PN 6075). These heads are cast from 356 alloy and heat-treated to T6 specs. After the seats are given a three-angle grind, the heads are fitted with swirl-polished, one-piece 2.02-inch and 1.6-inch stainless steel intake and exhaust valves. They have excellent low-lift flow (i.e. velocity, which equals very good low- and midrange response) and at .500 lift flow 233 cfm on the intake and 172 cfm out the exhaust ports-a great balance for a high-performance street setup.
The matching camshaft kit (PN 2102) features a split pattern. Using 1.5-ratio rocker arms, intake lift is .420 and exhaust is .442. The durations for intake and exhaust, at .050, are 204 and 214 degrees, respectively. Edelbrock's "Performer Link True-Rolling" timing chain set (PN 7802) is available to ensure accurate cam timing, and is a worthy upgrade from a stock replacement part. The Performer intake manifold (PN 3701) is a dual-plane, low-rise unit designed, just like the heads, for excellent low-lift velocity to give crisp low- and midrange throttle response as well as good horsepower production through 5,500 rpm. Finally, there's the Performer Series square-bore carburetors. The recommended carb for the smog-legal Performer Power Package is a 600-cfm unit (PN 1400) with electric choke plus provisions for EGR and a fuel vapor outlet.
To maximize the gains from the package, we're going to dump the stock exhaust manifolds and single exhaust and replace them with "shorty" headers and dual pipes. According to Edelbrock's in-house tests, a stock displacement 350, with the same 8.5:1 compression ratio and the same package of parts we'll be installing, is good for 310 hp at 5,000 rpm and 378 ft-lbs of torque at 4,000 rpm.
If all goes well, in the next couple of issues we'll showing the basics of the installation, then fit the new exhaust system, get the tune dialed in, and dyno test it. Since we'd dyno'd the rig in fresh, stock form, it'll be real interesting to see how much punch will be added to the formerly limp-wristed small-block, and what the Performer Power Package does for our old El Camino's all-around performance. Best of all, there's no wild guesses about what parts are suitable to use together to get the best results.