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Our test mule is a high-mileage '94 Z28 with an automatic transmission. With 125,000 miles of use, it's no spring chicken, but it is representative of what's out there in the $4,000 to $8,000 range. The stock LT1 long-block had no modifications prior to our Performer LT1 install and test, with the exception of Hooker 1 5/8-inch shorty headers, an aftermarket cat-back exhaust system, SLP cold air induction and a Holley throttle body airfoil. For a complete list of all mods done to our mule (including non-engine mods) check out the handy sidebar. Other than development cars at Edelbrock, Popular Hot Rodding was the first to install the Performer LT1 for media evaluation. They didn't want to mess it up, so they turned to one of the top late-model GM tuners in Southern California--Harv's Auto & Dyno Tune in Whittier. Harv St. Mary and Sean Baisden are no strangers to fuel-injected GM machinery, and LT1s are an old favorite with them. After taking a tour of the shop and seeing the level of work performed there, we were suddenly in our comfort zone. Sean Baisden, who would be doing the work on our Camaro, is the owner of several awesome GM machines, including an 11-second road-raced LT1 Corvette, so they knew they were in good hands. We should also note that they took the opportunity to change the oxygen sensors over to new Bosch units. Also, Edelbrock specifically specifies Champion RC-12YC plugs, which they complemented with a new set of Bosch spark plug wires. Since they didn't feel like chasing leaks later on, they used a complete gasket set from Mr. Gasket. As a precaution, they also replaced our worn timing set and pushrods with upgraded pieces from Comp Cams. The final piece of the puzzle was a throttle body swap. The factory 48mm air valve was replaced by a larger 52mm unit from Edelbrock. This swap meant eliminating the Holley airfoil because the Edelbrock unit has a cast-in airfoil. After making a few baseline dyno tests with the stock motor, Baisden spent the next two days pulling down the engine dress, intake manifold, cylinder heads and cam, then installing the new pieces. This can be done over a weekend by the do-it-yourselfer with a well-stocked tool box, but if you don't have much experience with late-model fuel-injected cars, this might be better left to seasoned pros like those at Harv's. Fortunately, you won't have to get into computer reprogramming like most blower kits, turbos or stroker motors, so your angst will be limited to the knuckle-scraping variety. As much as they wanted to dive into the cylinder heads, they resisted the urge to work them over. Under normal circumstances, it would be a good idea to do a simple bowl job and gasket match on these heads before bolting them on, but they really wanted to see how good they were right out of the box. Obviously, we were excited to fire it up for the first time, and the Performer LT1 heads and cam didn't disappoint. Once he was finished checking for problems and leaks, Baisden gave the LT1 a good bill of health. A check of the idle vacuum showed 11 inches versus 18 inches for the stock long-block. A quick drive around the block showed that most of what they wanted to know--they had a radically sharp throttle response off idle and a noticeable amount of additional pull through the midrange and top end. Without the R-compound Nittos, there would've been serious rubber laid on Whittier Boulevard! It's a good thing the brakes still worked great with 11 inches of vacuum (a big plus given the plans to add some serious SSBC brakes down the line). The only other thing needed was to know how much power? With the stock long-block, power peaked at 5,600 rpm and made 249hp at the rear wheels. If that sounds low, keep in mind that this is an automatic trans with a 2,800-rpm stall converter, so there is more than your average amount of driveline loss. Also, all runs were performed in second gear in order to keep the trans from downshifting mid-run. This typically holds power down because parasitic drag is greater in second gear. What's important is the relative increase, not the peak number. With the Performer LT1 heads, cam and throttle body, power peaked at 5,900 rpm and made 283 horsepower. That's a peak-to-peak gain of 34 rear-wheel horsepower. Better yet is the fact that horsepower was up at all points in the power curve, except at 3,700 rpm where our runs began (it was down 1 hp at that point). Power was up 46hp over the stock heads and cam by 6,000 rpm, but they suspected a lot of that gain was because the old valve springs were worn out. Still, we're guessing there are a lot of high-mileage LT1s out there that could benefit from a better set of heads with fresh valve springs. As you might expect on a motor with a hard-hitting torque converter (our Precision Industries Vigilante has to be one of the best out there) torque peaked down low at 3,700 rpm for both stock and Edelbrock combos. By 3,800 rpm, however, The Edelbrock Performer LT1 took the torque lead and by 6,000 rpm was up a whopping 40 lb.-ft. Clearly, the Performer LT1 intake port is not too small for a 350-inch LT1! They suspect there is even more power on the table with some rudimentary tuning via LT1 Edit, but we thought it better to let the out-of-the-box numbers do the talking. If some tuning is done later on, it will probably be to raise the idle speed and clean up the emissions for inspection time, but until then, they're just fine with the mule's street manners.We'd have to say the Edelbrock Performer LT1 combo is a homerun. It's relatively simple to install, the American-made parts fit well, the increase in power is in line with the cost of the parts, driveability on the street is excellent and reliability has proven to be good. For those stroker or blower customers wanting even more, keep your eye peeled for some bigger offerings down the road. If this is any indication, we can expect some more great news from Edelbrock.  Most of the first day was...  Most of the first day was spent tearing down the LT1. Here, the radiator, a/c condenser, accessory drive, brackets, intake manifold, cylinder heads, and the timing chain have been removed. The oil pan bolts have been loosened to speed the swap of the cam and timing gear. All gasket surfaces have been thoroughly cleaned to insure effective sealing later on.  Baisden has slathered on liberal...  Baisden has slathered on liberal quantities of Redline assembly lube and is now stabbing the cam into the LT1 short-block. In this shot you can see how helpful it is to have the radiator and condenser removed.  Ten years and 125,000 miles...  Ten years and 125,000 miles have taken its toll on the factory crank timing gear (left). Deep wear marks are evident on all teeth (as well as attendant stretching in the timing chain). The new Comp Cams gear (right) will make valve timing, once again, a precision affair.  Now for the obligatory "line...  Now for the obligatory "line up the dots" timing chain photo. Failure to do so will result in engine not go boom-boom.  Our Opti-spark distributor...  Our Opti-spark distributor had been replaced about 30,000 miles ago and was working fine, so we reused it. These aren't known as real long-life parts (ours could be considered borderline), so it's probably a good idea to replace. Note the splined water pump drive shaft just above the Opti. To prevent future leakage, it's important to insert the shaft with the lip of the new seal flapped to the inside--a seemingly impossible task. You don't want coolant dumping right into that distributor!  We're putting this timing...  We're putting this timing gear photo out of sequence to show you how the gear keyway is referenced to the bump on the balancer hub. That's important to know because the damper is referenced to the bump on the hub, as shown in the next photo.  Kent-Moore tool J-39046 is...  Kent-Moore tool J-39046 is required when removing or installing the balancer hub from the crankshaft on 1992-97 L99/LT1/LT4 engines. Here Baisden shows the alignment bump on the crank hub and crank damper. These must be aligned whenever installing the damper.  We ordered new exhaust gaskets...  We ordered new exhaust gaskets from Mr. Gasket, but we were so impressed with our old Flow Tech gaskets from Holley (part No. 99150AFLT) that we reused them for this installation. The Flow Tech gaskets feature multiple layers of dead-soft aluminum which crush to conform to the shape of the header flange and mounting surface. In the two years since we originally put them on, they have yet to leak and are still going strong.  The oil pump drive gear is...  The oil pump drive gear is basically the bottom half of a distributor. Since there is no typical distributor shaft on an LT1 but the oil system architecture is still the same as the Gen 1 small-block, this little piece remains. Don't forget to put it back in!  Time for the LT1 Performer...  Time for the LT1 Performer cylinder heads--which we took right out of the box and dropped right on the short-block. Note how the Mr. Gasket intake gaskets have convenient tabs that hold them into place while your intake manifold tries to do the watusi on them. The LT1-specific head gaskets are Mr. Gasket part No. 5715.  Baisden has dropped the new...  Baisden has dropped the new Comp pushrods in and is now finger tightening the rocker arms in place with the factory nuts. He'll crank down on them later.  It's easier to bolt on your...  It's easier to bolt on your LT1 intake already assembled with the throttle body, injectors, fuel rails and sensors attached. To spruce things up, Harv's completely disassembled the intake, cleaned it, then spray painted it with fresh aluminum paint. Now it looks new again. We probably should've flowed and cleaned our old injectors while we were at it, but we rationalized that we were trying to duplicate a worse-case scenario. Yeah, that's the ticket...  The best thing about re-using...  The best thing about re-using stock rocker arms is that it takes zero finesse. Just crank 'em on and forget about 'em!  Bosch supplied the world's...  Bosch supplied the world's first high-voltage ignition system in 1902 and has continued to supply superior wire sets for nearly 100 years. Bosch plug wires feature stainless steel Mag winding, a 100 percent pure silicone jacket, and a Kevlar reinforced core for maximum voltage, and a hotter, more powerful spark. Bosch is also a leader in oxygen sensor technology. It's a good idea to change your oxygen sensors every 50,000 miles and we were overdue.  We ordered our Comp Cams High-Tech...  We ordered our Comp Cams High-Tech pushrods (part No. 7940-16) prior to getting our Edelbrock Performer LT1 heads. These are the stock 7.200-inch length in a 5/16-inch diameter. After receiving our heads, the directions recommended .100-inch longer pushrods (Comp 7949-16 according to the instructions). Due to time constraints, we used the 7940-16 pushrods anyway with no problems.  On the dyno, our '94 Camaro...  On the dyno, our '94 Camaro Z28 with Edelbrock Performer LT1 heads, cam and throttle body cranked out 283 hp at 5,900 rpm. That's 34 hp and 300 rpm more than our stock baseline. We've got a really cool mpeg movie of our dyno run on the PHR website. Just click on www.popularhotrodding.com to see and hear it!  "Everything bolted up good...  "Everything bolted up good with no modifications necessary," says Sean Baisden of Harv's Auto & Dyno Tune. "All the components went back on without modification, which is pretty unusual for aftermarket parts. It made good power--the power they said it would make--which again is rare for most companies. I would definitely recommend to somebody looking for another 30 or 40 rearwheel horsepower that they look into the Edelbrock upgrade. It's a near perfect combination. It's also a good basis for additional add-ons. For a stroker, I'd definitely want to port these more or wait 'til the bigger 200cc heads come out."
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