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LS1 Chevy Corvette GM Performance Parts - Aspiration Rehabilitation

With Some Help From GMPP, We Add 78 Rear-Wheel Horsepower To This Already Stout LS1 Corvette.

Dan Ryder Feb 1, 2008
Sucp_0802_01_z Ls1_corvette_gm_performance_parts Burnout 2/15

In the February '08 issue of Super Chevy ("Totally Exhausted") we began our quest to gain or exceed Z06 power output from a stock LS1 with just bolt-ons. After the flawless installation of a complete SLP exhaust system and some tuning, our '99 Corvette test vehicle pumped out 338 hp and 348 lb-ft of torque at the wheels, which resulted in a gain of 25 hp and 24 lb-ft of torque. With an estimated 398 engine horsepower, we were only seven ponies shy of gaining factory-rated Z06 power.

What to do next? After putting in a call to Dr. Jamie Meyer at GM Performance Parts, we decided to bolt on a set of GMPP's LS6 CNC-ported cylinder heads (part #88958665) and LS1 Hot Cam (Part #1248003). In order to install these components atop our LS1, we would have to change the intake manifold over to an LS6-styled unit (part #88894339). Once again, what were our options? We had plenty, but we decided to stick with components from within the GM family. By keeping with the General's front line, we were damn near guaranteed a proper fit, ease of installation, and excellent power gains with total streetability.

Sucp_0802_04_z Ls1_corvette_gm_performance_parts Cylinder_head 3/15

Shown here is the LS6 CNC-ported aluminum cylinder head as received from GMPP. These cylinder heads have received the same CNC-port job as the LS6 race-only cylinder heads, the only difference being that the units we are installing maintain a 65cc chamber-resulting in a pump-gas friendly 10.5:1 compression ratio. The LS1 head has a noticeable hump (slowing flow) within the intake port, while the LS6 unit has a more direct, smoother design.

In order to keep with the program we called upon Mike Morgan, Parts Manager at Lattof Chevrolet in Arlington Heights, Illinois, for our incidentals such as cylinder head gaskets, cylinder head bolts, valve cover gaskets, exhaust header gaskets, timing cover and water pump gaskets-all of which were GM production style components. Lattof Chevrolet has been in business since 1936 and selling GM Performance Parts for approximately 15 of those years. Whether you need something small like a gasket or something as large as a crate engine, Lattof can provide.

After filling the hatch of our C5 with the aforementioned products, we headed south to South Amboy, New Jersey, to visit Crazy Horse Racing-a well-known shop within the Ford racing world. Following a recent discussion with Chris Winter (owner of Crazy Horse), we were pleased to hear that he would be entering the Chevrolet fray as well. What better way to kick it off than with our '99 Corvette project car.

Let's get it on!

Needless to say, we were extremely happy with the results of this two-part project-the Dynojet read 411 hp and 385 lb-ft of torque-that's a gain of almost 100 hp and 62 lb-ft of torque from our initial baseline of 312hp and 323 lb-ft. Estimated flywheel horsepower checks in at approximately 475 hp, which is 70 more horsepower than the C5 Z06 ... something we'd like to call total annihilation. Due to impeding deadlines and bad weather we were unable to get the C5 to the strip for some after numbers, but we figure we should see times in the 11.90s on the street tires, at around 115 mph.

That being said, with a little over $5,000 in parts for both installations on the project, we've turned out a C5 Vette that will slaughter just about any Z06 it encounters.


SLP Performance Parts
Toms River, NJ 08755
Danbury, CT 06810
Chevrolet Performance Parts
Detroit, MI 48232
Crazy Horse Racing
South Amboy, NJ 08879



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