Michigan Motorsports Camshaft Thrust Retainer Plate Kit - NonVVT LS

In this review the Michigan Motorsports camshaft thrust retainer plate kit is assessed for LS builders and engine rebuilders who need a stronger, more serviceable alternative to the factory GM plate. The bottom line: this kit replaces GM part 12589016 with a heavy duty flat plate and includes the ARP 134-1002 bolt kit, making it the best straightforward upgrade for nonVVT Gen III/IV LS engines that reduces the risk of stripped or seized fasteners and improves long term serviceability.

Key Features

• Direct Replacement: Fits and replaces GM 12589016 for a clean OEM fitment that makes installation straightforward on compatible nonVVT LS engines.
• Heavy Duty Flat Plate: The flat style plate removes the weak countersunk torx geometry so bolts are far less likely to strip during disassembly.
• Includes ARP Bolt Kit: Supplied ARP 134-1002 flathead bolts provide higher clamping force and resist loosening under sustained high RPM conditions.
• Built for NonVVT LS Engines: Designed for 4.8, 5.3, 5.7, 6.0 and 6.2L nonVVT LS configurations so compatibility with common Gen III/IV cores is clear.
• Proven in Performance Builds: Used by professional LS builders for street, strip and endurance applications where strength and repeatable torque retention matter.

Who It's For

This kit is aimed at engine builders, performance enthusiasts and anyone doing a rebuild on a nonVVT LS1, LS2, LS3, LQ4 or LQ9 who wants to avoid fragile factory fasteners and improve long term serviceability. It is especially useful in high RPM or racing builds where bolt retention and ease of future disassembly are priorities.

Those who should look elsewhere include owners of VVT-equipped LS engines; this kit is not intended for VVT setups and the correct countersunk style must be used where variable valve timing components require the factory geometry.

Pros & Cons

Pros

• Higher reliability than the factory countersunk design, reducing risk of stripped bolts.
• ARP 134-1002 bolts add proven clamping force for high RPM confidence.
• Direct GM 12589016 replacement for easy fit and straightforward installation on compatible engines.
• Trusted by professional builders for durability in performance applications.

Cons

• Not compatible with VVT LS engines, so buyers must confirm their engine type before purchasing.
• Upgraded bolts and thicker plate may require careful torque procedures during installation to avoid installation errors.

Specifications

Brand	Michigan Motorsports
Replacement For	GM part 12589016
Included Hardware	ARP 134-1002 flathead bolt kit
Compatible Engines	NonVVT LS 4.8L, 5.3L, 5.7L, 6.0L, 6.2L (Gen III/IV)
Plate Style	Heavy duty flat style retainer
Typical Use	Street, strip, endurance and engine rebuilds

Our Verdict

The Michigan Motorsports thrust retainer plate kit is a practical, value-minded upgrade for any nonVVT LS rebuild where durability and serviceability matter. It replaces the fragile factory countersunk design and adds ARP fasteners for peace of mind in high RPM and performance applications, making it a smart buy for builders who want a long lasting, easily serviced camshaft retainer solution.

Frequently Asked Questions

Is this compatible with VVT LS engines?
No. This kit is designed for nonVVT Gen III/IV LS engines and is not suitable for VVT applications.

Does the kit include bolts?
Yes. The package includes the ARP 134-1002 flathead bolt upgrade for improved clamping force.

Will this fit LQ4 and LQ9 engines?
Yes. It is listed as a direct replacement for common nonVVT engines including LQ4 and LQ9.