712500M : Flywheel and Luk Clutch kit for LS-Series / Gen 3 engines (#712500M)

Retail Price: $673.96

Advance Adapter

This custom clutch kit is designed to adapt the Gen III / LS series to a GM manual transmission (M21/M22, SM420, SM465, NV4500). The clutch kit includes a custom flywheel, 11mm flywheel bolts, 11" LUK pressure plate & disc, pilot bushing spacer, throw-out bearing, 10mm bellhousing bolts, 10mm lock washers, XRP dowel bolts.

Note: The flywheel included in this kit was developed for exclusive use for Advance Adapters. The flywheel offsets the distance of the disc surface .400 inch towards the transmission to make up for the shallow crank (.340 inch) flange on the LS engines. This design allows full clutch disc spline engagment on the transmission input shaft. The flywheel is relieved on the backside to maintain a 35lb weight.

Note: We can also use this clutch kit with Gen III / LS Engines to Jeep manual transmission (AX15 / NV3550) & Ford manual transmission (NP435/T-18). When using these transmissions the throw-out bearing retainer must be machined!!! Ford 4 speed applications will need a different clutch set !!

Gen III / LS Engines

The new style Gen III / LS series engines (4.8, 5.3, 5.7 LS1, 6.0, 6.2) all have the same crank stick out which is .400" closer to the block than the old 350 V8. The Gen III / LS series crank bolt pattern is different than any other GM crank as to the bolt pattern on the flex plate. Only Gen III / LS series flywheels fit these engines!!! The Gen III / LS series engines are internally balanced block which is different than the 1986 & newer standard GM blocks (305,350).

Note: The flywheel in this kit does not fit the older 6.0L with cast iron heads & 4.8L that was used with manual transmissions.

Note: Kit will not fit 2014 & up Gen V engines (New LT1 V8 & 4.3 V6, 5.3, 6.2)

The GM Generation III & IV blocks are classified as a 4.8L, 5.3L, 5.7L(LS1), and 6.0L. These blocks have gained popularity because of the emission controls required when performing a engine swap. A few things to consider when using a Generation III V8 block are as follows: All fasteners are metric. The heads of a Gen III are wider than an early GM V8, so the exhaust manifolds are tough to fit between the frame rails on most vehicles. The exhaust on the driver’s side can be a problem for mechanical clutch linkages. The oil pan is aluminum and cannot be modified. This can cause some problems on vehicles requiring oil pan modifications. We recommend the installation of a Gen III into the following vehicles: Jeep TJ, YJ, and CJ7 (CJs may be required to use a header system), Toyota Land Cruiser, full size Chevys, and any other vehicle with a minimum of a 25” inside frame width.

Transmission Combinations: The Gen III engines have the same block bolt pattern as the early GM with the exception of one bolt hole. When bolting an earlier GM transmission or one of our bellhousings to the Gen III block, you will only be able to use 5 bolts on some bellhousing kits. The Gen III engine used a different crank stickout from the back of the block and a different crank bolt pattern. This means the early style flywheels and flexplates will not bolt to the new Gen III blocks. The stock flywheels and flexplates from the Gen III blocks are also unique with regard to the clutch bolt pattern and the torque converter bolt pattern. We have designed two kits for either a manual transmission or an automatic.

There are some Gen III blocks that do not have the recessed crank. This kit will not work on these blocks. One block that we know of is the 6.0L with cast iron heads and the 4.8 or 6.0 engines coupled only to a stock manual transmission in 1999 to 2003. A custom flywheel would have to be made to work on these block P/N CF720000.

The kit designed to fit a manual transmission is PN712500M (Luk Clutch) or PN712500M-CF (Centerforce clutch). This kit includes a flywheel, flywheel bolts, 11” pressure plate & disc, bolts for the pressure plate, pilot bushing spacer, release bearing, and metric bolts & washers for the bellhousing. The above listed kit works with our bellhousing kits P/N 712525, 712548, 712549, 712560V, 712561V, 712565V, 712567V, 712576, 712577, and 712591V. A special starter, P/N 22-0002, is required if using bellhousings 712560V, 61V, 65V, 67V and 712591V 716155 GEN III BUSHING & 716154 GM

The kit designed to fit the TH350 or 700R automatic transmission is PN712500A; and for the TH400 transmission PN712500A4. These kits include a modified flexplate (drilled for a early GM torque converter), flexplate bolts, crank spacer bushing.

Exhaust: The truck manifolds fit the majority of applications with the exception of the Jeep CJ. The Jeep CJ can use a Gen III Camaro manifold or exhaust headers that we manufacture. On our NV4500 bellhousing kits, the truck manifolds also have some clearance issues with the slave cylinder. We sell a slave cylinder bracket for a NV4500 and Gen III engine application. We also offer a rear dump header similar to truck manifolds, P/N 717045. PN717040 Jeep CJ Gen III Fenderwell Header PN717043 Gen III Center Dump Header PN716286 Slave Cyl. Brkt. (NV4500 w/ truck manifolds)

Vacuum Lines: You will notice that the GEN III block has no provision for vacuum lines. There is a small port on the back of the intake manifold that can be used. First, pull out the black plug on the intake manifold by holding pressure on the gray ring. Once the plug is out, drill and tap the black plug for a 1/8” pipe thread. Use a 90 degree 1/8” pipe by 3/8” barb adapter and thread it into the tapped plug. Press the plug back into the manifold and attach the hose.

Radiators: The Gen III requires a steam release port which is a standard feature on our radiators that the part number ends with a (-LS) at the end. The Gen III also require smaller water inlets and outlets on the radiators. The Gen III engines recommend a 50/50 mixture of Dex-cool and water.

Fan: We recommend using an electric fan in most installations. Our Spal fans allow for ample clearance in the engine compartment providing for good air circulation. We offer a Spal fan kit (to fit our radiator) under P/N 716670. This fan is rated at 2070 CFM.

Wiring: Installing the Gen III is fairly simple; however, depending on the year of the vehicle, coupling to the stock gauges may require a vehicle service manual. For example, on a Jeep TJ we retained the stock Jeep sending units and attached them to the GM block (oil pressure, temperature, and fuel level). All of them work fine except the tachometer (in which we installed an aftermarket one). Since we used the stock sending units and because the Jeep TJ had a computer controlled stock engine, the Jeep computer thinks that the original engine is still sending information. Vehicles that were not originally computer controlled may just need new dash gauges coupled to the Gen III sending units.

Throttle Linkage: The throttle cable that comes on most Gen III engines has a standard cable connection which can be fitted to most gas pedals. A new, larger access hole may need to be drilled in the firewall where the stock cable was originally located.

Fuel: The Gen. III fuel rails have anywhere between 50-60 pounds of fuel pressure! Only approved high pressure hose and fittings should be used. The Gen III engines need a minimum diameter of 3/8” line on the pressure side, and a minimum of 5/16” on the return side (3/8” is best for the return line). Depending on the year, model, and make of your vehicle, you will need to find out what type of fuel delivery system your vehicle was equipped with and what type of pressure it was running. For example, a Jeep TJ used a fuel pump that was internally regulated in the fuel tank at 46 psi. Since the Jeep regulated the pressure at the tank, it did not run a return fuel line. On this installation, we opted to run two new 3/8” lines; one pressure and one return. The pressure line needed to be installed by drilling and installing a bulkhead-type “AN” fitting alongside the stock Jeep pump assembly. A fuel tank pickup also had to be installed. The old “pressure” line out of the Jeep tank was used as a return line from the Vortec. To use this connection, we had to remove the stock internal regulator. This is just an example of one application we encountered.

The Gen III crank is almost flush with the back of the block


VIN 8th Digit RPO Code Displacement Name
G LS1 5.7L LS1
S LS6 5.7L LS6
VIN 8th Digit RPO Code Displacement Name
V LR4 4.8L Vortec 4800
T LM7 5.3L Vortec 5300
Z L59 5.3L Vortec 5300
U LQ4 6.0L Vortec 6000
N LQ9 6.0L Vortec HO or Max
VIN 8th Digit RPO Code Displacement Name
P LM4 5.3L Vortec 5300
B L33 5.3L Vortec 5300 HO
VIN 8th Digit RPO Code Displacement Name
U LS2 6.0L LS2
Y L76 6.0L L76
2 L77 6.0L L77
W LS3 6.2L LS3
J L99 6.2L L99
E LS7 7.0L LS7
VIN 8th Digit RPO Code Displacement Name
C LY2 5.7L Vortec 4800
A L20 5.7L Vortec 4800
J LY5 5.3L Vortec 5300
0 LMG 5.3L Vortec 5300
4 LMF 5.3L Vortec 5300
K LY6 6.0L Vortec 6000
G L96 6.0L Vortec 6000
VIN 8th Digit RPO Code Displacement Name
M LH6 5.3L Vortec 5300
3 or 7 LC9 5.3L Vortec 5300
L LH8 5.3L Vortec 5300
P LH9 5.3L Vortec 5300
H LS2 6.0L LS2
Y L76 6.0L Vortec Max
5 LFA 6.0L Vortec 6000 hybrid
J LZ1 6.0L Vortec 6000 hybrid
8 L92 6.2L Vortec 6200
2 L9H 6.2L Vortec 6200
F L94 6.2L Vortec 6200

Top Reviews


by John, from Tucson/AZ

Nice Quality Kit

Overall a good kit. Everything went together smooth with my 5.3L to SM420 conversion. One thing that would be nice is a pilot bearing. I went to the local GM dealer and picked one up for a LS series motor. I also had to get different length bolts for my bellhousing. Again not a major hold up, took a quick trip to the local hardware store and got the bolts I needed.

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