There comes a time in any car's buildup when you're no longer happy with bolt-ons. Although the less expensive modifications have proven to be beneficial to performance, the brick wall is finally in your face, and the next leap is a big one. Some prefer to steer away from such a move, but for those of us who can't settle for good, the next frontier generally means getting into the engine. For us, good becomes gooder with a new cylinder head and intake package.
Edelbrock's recently introduced...
Edelbrock's recently introduced Performer LT1 aluminum head represents the latest in cylinder head technology. They come bare or complete with springs, valves, and rocker arm studs and offer big gains in power. The aluminum knocks about 70 pounds off any LT1's nose, and with its 2.02/1.55 valve sizing, it offers freer breathing for our stock 350-inch short-block.
When most people think of cylinder heads, they're often daunted by the huge variety of offerings for the small-block Chevy. Although it seems like a good thing at first, research will soon reveal there aren't as many options for LT1 enthusiasts because there simply aren't as many heads on the market. Many companies skipped the LT1 market and went straight for the LSX scene, but now that LT1 engines are in great abundance, several companies are now refocusing attention to the Gen II small-block introduced in 1992.
Edelbrock-which has been on an absolute tear recently with all sorts of new cylinder heads for various American V-8 applications (both popular and obscure)-recently released a line of aluminum heads for both the LT1 and high-port LT4 engines. Yes, following along in its Performer RPM line of heads, these new castings promise Gen II owners something to look forward to with respect to performance, value, and weight savings. The best part about it is that Edelbrock sells them either bare for the hardcore engine builders or as a complete assembly for guys like us who like to bolt-on and go.
Headin' OutEdelbrock's Performer LT1 aluminum cylinder heads feature many goodies that you'd expect, including generous 2.02/1.55 valves, CNC port-matched runners, and high-lift valvesprings for use with hydraulic roller camshafts. Unlike some other heads on the market, Edelbrock goes a step further and uses steel thread inserts on all the attachment points for more secure fastening. If any of you out there have ever stripped a thread in an aluminum cylinder head, then you can really appreciate this attribute.
Looking down the intake port,...
Looking down the intake port, you can see how Edelbrock gives each head a CNC-profiled port match. With its 170cc intake runners, the low-profile bronze valveguides ensure excellent midlift velocity for greater torque, horsepower, and more importantly, snappy throttle response for our 4,000-pound behemoth.
Also, Edelbrock's heads bolt right on without the use of any special-length fasteners or exotic valvetrain components. This keeps costs down as you take the plunge into the top-half world of more power. Available bare or complete, they're sold separately, and we went with the ready-to-run units listed under part number 61909. To install them, we picked up a set of new GM head bolts procured from the local Chevy dealer to do away with the factory torque-to-yield bolts.
To complement the heads, we decided to ditch the factory intake manifold and go with Edelbrock's matching Performer LT1 intake manifold. Aside from offering larger ports that properly match up to its heads, Edelbrock's manifold also has larger openings on the throttle body side that can accommodate 58mm throttle bores. Although our car is only equipped with a 52mm twin-bore unit (stock is 48mm), it's good to know that should we choose to upgrade in the future, the option is there for us.
It's interesting to note that a version for LT4s is also available that includes the taller port location. Edelbrock also offers LT4 cylinder heads for those who want to go beyond their '96 C4's 330hp rating.
Rounding out the installation is a set of hardened 7.3-inch pushrods and self-aligning roller rockers from Comp Cams. With its roller bearing mount and lightweight aluminum construction, the 1.5 roller rockers (part number 1015-16 for the set) will help us pick up some incremental power from reduced parasitic friction on the top half. It should be noted that it's not necessary to replace them when using the Edelbrock heads, so if you wanted to, you could reuse the stock rockers.
 Edelbrock's Performer LT1...  Edelbrock's Performer LT1 intake is a direct replacement for the stock LT1 piece, but it offers larger 58mm throttle body openings and , of course, runners with greater cross sectional are for more airflow and power. The intake runners are port-matched right out of the box, so all we have to do is swap out the stocker. |  Aftermarket roller rockers...  Aftermarket roller rockers are a great way to free up parasitic frictional losses and maintain proper rocker arm geometry in performance applications. We ordered ours from Com Cams in the stock 1.5 ratio for use with the 3/8-inch rocker studs. Because LT1s use a self-aligning tip and require a narrow body to clear the valve cover bolts stands, conventional SBC rockers won't work here, so make sure you get the right ones. You'll also need a set of proper-length hardened pushrods, so go for the 7.3-inch ones like we did. It's available under part number 7949-16 for a complete set. |  "Big Tom" O'Sullivan gets...  "Big Tom" O'Sullivan gets busy with the ratchet and starts unbolting the intake manifold. Most of the fasteners come out with a 9/16-inch-deep socket, while all the electrical items simply unplug from their respective locations. Of all the fuel-injected small-blocks we've come across, the LT1 is one of the easiest to service, especially when there's full access to it. And unlike an F-body Camaro, you're not encumbered by windshields, shock towers, or other items in Caprice that would other wise inhibit mechanical progress. |
 With a quick twist of the...  With a quick twist of the prybar, "Big Tom" pops the intake off and starts on the cylinder heads. |  To access the head bolts,...  To access the head bolts, you'll need to undo the factory self-aligning rocker arms. They come off with a 9/16-inch-deep sockets. Since we didn't intend to reuse them, we just put everything in the trash bin. If you intend to reuse the factory rocker arms, try to keep everything numbered so that they go back into the same location. |  To access the bolts that secure...  To access the bolts that secure the alternator bracket to the passenger-side cylinder head, you'll have to undo the power steering pump first. This requires a special puller to remove the pulley and a full dreaming to the steering system. Instances like this are proof positive that professional help is the best help. |