The T-H Marine Z-Lock JPZ-6-DP 6-Inch Manual Jack Plate is one of the most popular performance upgrades available for outboard-powered boats. Designed to improve engine efficiency, propeller performance, handling, and top-end speed, this heavy-duty jack plate provides 6 inches of setback and 5 inches of vertical engine-height adjustment, allowing boaters to fine-tune their setup for maximum performance.
 
Built from 1/2-inch aircraft-grade aluminum, the Z-Lock utilizes T-H Marine's innovative interlocking side-plate design to provide exceptional rigidity and strength while securely locking the engine in position.
 
The result is a stable mounting platform capable of handling today's high-performance V6 outboards up to 300 horsepower.
 
Why Add a Jack Plate?
 
One of the biggest restrictions to outboard performance is turbulent water flowing behind the transom.
 
By moving the engine 6 inches rearward, the propeller operates in cleaner water, improving efficiency and allowing the boat to carry the bow with less trim. The ability to adjust engine height is equally important.
 
Raising the engine can reduce lower-unit drag, improve RPM, increase fuel efficiency, and often produce measurable gains in top speed. Lowering the engine can improve bite, acceleration, rough-water handling, and water pressure when conditions demand it.
 
Properly set up, a jack plate is often one of the most effective bolt-on performance upgrades available for an outboard-powered boat.
 
Heavy-Duty Z-Lock Construction
 
Unlike traditional manual jack plates that rely solely on clamping force, the Z-Lock system uses matching interlocking side plates that mechanically lock the engine position in place.
 
This design helps prevent side movement under load while improving overall rigidity and handling consistency.
 
The JPZ-6-DP is constructed from corrosion-resistant aircraft-grade aluminum with stainless-steel hardware and provides approximately 5 inches of vertical adjustment, allowing precise engine-height tuning without the complexity of a hydraulic system.
 
Mercury Racing & Mercury Marine Fittment
 
The T-H Marine JPZ-6-DP is commonly used on Mercury Racing and Mercury Marine outboards up to 300 HP. Popular applications include Mercury Racing 245 Carb, 260 EFI, 280 ROS, 300 Drag, 300 ROS, 300X, 300XS, and numerous offshore and lake-race combinations.
 
It is equally at home on Mercury Marine XR2, XR4, XR6, XRi EFI, Laser EFI, 150 HP, 175 HP, 200 HP, 220 Laser EFI, 225 HP, 225 Pro Max, 250 EFI, 250XB, Optimax, and Pro XS models. The plate is also commonly used with modern Mercury Racing 250R and 300R outboards where a lightweight, maintenance-free manual jack plate is preferred.
 
Specifications
 
The T-H Marine JPZ-6-DP features 6 inches of setback, approximately 5 inches of vertical adjustment, heavy-duty 1/2-inch aircraft-grade aluminum construction, and compatibility with standard BIA outboard mounting patterns.
 
The plate is designed for V6 outboards and carries a maximum recommended rating of 300 horsepower.
 
Final Thoughts from Buckshot Racing #77
 
The T-H Marine Z-Lock JPZ-6-DP 6-Inch Manual Jack Plate remains one of the best values in performance rigging. Its combination of strength, simplicity, and adjustability makes it a favorite among bass boat owners, performance boaters, and Mercury Racing enthusiasts.
 
Whether you're dialing in a 260 EFI, optimizing a 300R, setting up a 300X lake racer, or improving the efficiency of a Pro Max or XR6, the JPZ-6-DP delivers the setback and engine-height adjustment needed to unlock your boat's full performance potential.