ACT 1998 Chevrolet Camaro HD/Race Sprung 6 Pad Clutch Kit
The ACT GM9-HDG6 is a Heavy Duty pressure plate and 6-pad sprung race disc for the LS1 Camaro. Our listing is for the 1998 Z28 and Z28 SS with the 5.7L LS1 and the six-speed manual. It is the clutch people look for once a stock or mild street clutch starts slipping in third and fourth after a cam, heads, a power adder or sticky tires, or when a car spends real time at the drag strip or road course.
The pressure plate bolts to the flywheel and clamps the disc against it, so engine torque passes through the disc splines into the T56 input shaft. When the clamp load or the friction material cannot hold the torque, the disc slips, heats and glazes. ACT rates GM9-HDG6 at 908 ft-lb of torque capacity measured at the crank, which ACT puts at 82% over the factory clutch.
The kit has three pieces: the GM015 Heavy Duty pressure plate, the 6280320 6-pad sprung race disc and the ATGM026 alignment tool. The disc is 11 in (280 mm) with ceramic pads and a 1.125 in input spline. The sprung center damps driveline vibration, but a 6-pad ceramic disc still engages much more abruptly than an organic street disc. ACT describes the feel as light to moderate pedal effort, aggressive engagement and OE to mild gear rattle, and recommends it for high horsepower street or race use. If the car is mostly a daily driver, the GM9-HDSS street version uses the same pressure plate with a full-face organic disc.
A slip test is simple: in fourth gear at around 2,500 rpm, go to full throttle and watch the tach. If RPM rises faster than road speed, the clutch is slipping. Rule out a leaking slave or air in the hydraulics first, since a release system that never fully lets go also causes slip and hard shifts. Our clutch slipping causes and fixes page and the slipping diagnosis guide walk through it, and clutch chatter causes covers takeoff shudder.
Our listing is titled for the 1998 Chevrolet Camaro. ACT catalogs GM9-HDG6 for the 1998-2002 Camaro Z28 and Z28 SS 5.7L LS1, the 1998-2002 Firebird Formula and Trans Am LS1, the 1997-2004 C5 Corvette including the LS6 Z06, the 2005-2013 C6 Corvette LS2 and LS3, and the 2004-2006 GTO. It does not fit V6 Camaros or the earlier LT1 cars. ACT notes the kit must be used with a flat flywheel, or its 600585 flywheel on LS2, LS3 and LS7 engines. If your car has a swapped engine, an aftermarket flywheel or a non-stock transmission, send us the year and VIN before ordering. More Camaro drivetrain parts are on our Camaro parts page.
Need more than 908 ft-lb or a lighter pedal? ACT's twin disc HD street kit is the next step for the same car. For gearbox trouble found during the job, see T56 problems and rebuild cost.
| Brand | ACT |
| Part number | GM9-HDG6 |
| Fits | ACT 1998 Chevrolet Camaro HD/Race Sprung 6 Pad Clutch Kit |
| Vehicle fitment | Chevrolet Camaro Hd/Race Sprung 6 (1998) |
| Type | Clutch Kits - Single |
| Condition | New |
| Ships | Same business day (in stock), from the USA |
| Warranty | 1-year |
ACT lists it for the 1998-2002 Camaro Z28 and Z28 SS and the 1998-2002 Firebird Formula and Trans Am with the 5.7L LS1. Our listing is titled 1998, so send us your VIN for a later car and we will confirm.
No. The kit is the GM015 pressure plate, 6280320 6-pad sprung race disc and ATGM026 alignment tool. The LS1 Camaro uses a hydraulic slave with the bearing built in, which is a separate part.
ACT recommends it for high horsepower street or race use. The 6-pad ceramic disc engages aggressively, so stop-and-go driving takes more care. For a mostly street car, the GM9-HDSS organic disc version is the smoother choice.
ACT rates it at 908 ft-lb measured at the crank, 82% over the factory clutch.
Yes, somewhat. ACT says its Heavy Duty pressure plates typically raise pedal effort 15-40% depending on the application, and describes this kit as light to moderate effort.
ACT says the kit must be used with a flat flywheel. A stock LS1 flywheel in good condition can be resurfaced; one with cracks or deep hot spots should be replaced.
