Edelbrock LT1 Performance Package - The Equalizer

In the last decade, aftermarket giant Edelbrock has become a savior of sorts to legions of fans. Yes, their mainline products for popular engine families like the small-block Chevy remain the great value they always were, but to many gearheads who worship at the altar of lesser engine families like Pontiac, AMC or the Ford FE, Vic and his elves have rained down a cornucopia of specialized products with clock-like regularity. All this wealth of horsepower--often for forgotten powerplants--has leveled the playing field with the small-block Chevys of the world. It's fair to say the big "E" in Edelbrock could also stand for "Equalizer," and that's just what Edelbrock has done again with their LT1 Performer combo.

For the most part, the LT1 is a small-block Chevy, but unfortunately, all bets are off when it comes to activities above the fire deck. Reverse-flow cooling, Opti-spark ignition, and a Gen IE manifold bolt pattern all conspire to make LT1 induction about as common as Ford Y-block parts. A few manufacturers have made an attempt at LT1 induction (most notably AFR), but they are, by and large, modified production LT1 parts or LT4 parts. In short, LT1 owners have had to live at the fringes just like Pontiac or Oldsmobile lovers.Prior to the Performer LT1 heads and cam, the weapon of choice for LT1 owners on a budget has been the LT4 swap. For about $2,500, you can buy all the parts needed to convert your LT1 over to LT4 spec. (The LT4 was the one-year-only 1996 Corvette mill rated at "only" 330hp. It came in all 6-speed equipped Corvettes in 1996.)

Comparison of the Performer LT1 combo to the LT4 swap (including LT4 Hot Cam) is inevitable. From a cost standpoint, it's almost a dead heat with a small advantage going to Edelbrock. From a power standpoint, the LT4 heads and intake with a Hot Cam is going to take a slight advantage, but only if the computer's fuel calibration is maximized. Ironically, the Performer LT1 ports and cam profile are not as radical as the LT4, so your stock computer calibration (as we found out) will work just fine without any tuning. Not so for the LT4 with the Hot Cam. Advantage: Performer LT1.

Based on our experience, we'd have to say the Edelbrock versus LT4 is a close battle. The important thing is that LT1 fans now have a choice. Like the factory-designed LT4 bits, the Edelbrock parts are top notch and fit to your production block and intake with factory precision. The outward appearance of the Performer LT1 heads are so stock-appearing that Edelbrock didn't even bother getting a CARB exemption because it's technically a factory replacement. That is, a factory replacement that happens to make as much as 46 horsepower over the stock heads!

Unlike the LT4 swap (heads, cam, a different intake manifold and higher ratio 1.6 roller rockers) the Edelbrock Performer LT1 system lets you keep your stock intake manifold and rocker arms. You can upgrade your rockers with the Edelbrock heads if you want, but the Performer LT1 cam and valve springs are engineered together to provide plenty of lift and flow.

Edelbrock's cam is an interesting piece. It specs out on paper as being larger than the popular LT4 Hot Cam, but that's a little deceiving. Because most LT4 Hot Cams are installed with taller self-guided 1.6 ratio roller rockers (which came standard on the LT4 in 1996), the Hot Cam ends up being about the same size as the Edelbrock cam in practice. The Edelbrock bumpstick achieves its lift and duration specs with a stock 1.5:1 rocker arm, which is exactly how we installed it in our '94 Z28 test vehicle. This makes the Edelbrock cam cheaper and easier to install with no downside to power. So if you're in the market for just a cam and can only afford to buy the valve springs and not rocker arms, this is a good one to consider. If you're planning on running your LT1 on the street, make note of the fact that the Performer LT1 cam is not street-legal and could raise a few eyebrows come inspection time. As an alternative, Crane Cams offers a Powermax 2050 cam (formerly Compucam 2050) which is 50-state legal (CARB E.O. No. D-225-55, part No. 104241) and specs out to 280 degrees advertised duration and 218 degrees at .050-inch lift. Valve lift with a 1.5:1 ratio rocker is .498 inch and the Powermax is ground on a 116 degree lobe separation angle.

So what about the heads? We'll let Edelbrock project engineer, Ulises Gonzalez, tell you in his own words: "We were trying to make a cylinder head that would beat the stock head for a while. We basically took the same port configuration from our E-Tec heads and adapted it to the LT1. We did this in combination with a cleaner chamber design--meaning we removed the tooling lug in the stock LT1 which gets in the way of the flame travel. The ports are optimized for high-speed flow and for optimum swirl. The LT4 is a different head--it's a bigger piece with a port near 195cc. Ours is 170cc, which accelerates the airflow."At 170cc intake port volume, the Edelbrock head isn't as big as it could be, so there will no doubt be some vocal message board heroes who will shout foul. Those folks are missing the point for two reasons: the LT4 head is already serving that part of the market very well, and a larger-than-LT4 head would most certainly require bigger injectors, stronger bottom-end internals and a reprogrammed fuel map. Not bolt-on stuff. "The LT4 will give you more rpm and slightly more power above 5,500 or 6,000 rpm," says Edelbrock's Gonzalez, "but ours will give you optimum power from 2,500 rpm on up. In the next year or so we will be coming out with a 200cc version of this head, which will be comparable to the LT4."

We were literally able to bolt all the Edelbrock stuff on and strap it to the dyno with zero programming and no fuel system upgrades. The package idles fine with a nice lope at 650 rpm and torque is explosive off the line, thanks to good low-speed port velocity and a cam with a relatively tight lobe separation angle. We did connect a wide-band air-fuel ratio monitor to the exhaust during dyno testing and found everything to be well into the super safe zone.Valve sizes on the Performer LT1 are 1.94 inch for the intake (the same as a stock LT1) and 1.55 inch for the exhaust (versus 1.50-inch for stock). Valves have a two-angle 45/30 valve job with a radius under the seat, which gives the Edelbrock a huge flow advantage over the stock single-angle valve job. Valve springs on the assembled heads are plenty stout with 120 lbs. on the seat at a 1.80-inch installed height. By comparison, stock LT1 springs are 85 lbs. at the seat while typical LT4 upgrade springs run around 105 lbs. According to Gonzalez, "Our spring allows you to run the engine another 500 to 1000 rpm more than the stock spring." As we shall see, that translates into some very useable power at the top end--not easy to accomplish on a mill with over 100K on the clock.