If you're diving into the world of high-performance engines, let me tell you, the ACL Race Series Engine Bearings are a game changer. These aren't just any bearings; they’re crafted with a unique blend of design, metallurgy, and engineering that really delivers when you push your engine to the limit. I’ve used these in my builds, and they stand up to the high RPM conditions that performance enthusiasts crave.

What sets these bearings apart? For starters, they feature a high-strength overlay plate that’s thinner than what you might find in standard options. This isn’t just for show; that reduced thickness means better fatigue properties, which translates to longevity and reliability when you’re out on the track or tackling tough trails.

Each rod bearing comes with hardened steel backs. This isn’t just a fancy spec; it really helps support the bearing lining and keeps everything snug in the housing. And speaking of snug, the increased crush on these bearings enhances retention, so you won’t have to worry about them shifting around when you’re pushing your engine hard.

One of the coolest features is the elimination of flash plating on the back of the bearings. This might sound technical, but it’s all about improving heat transfer. Better heat management means better performance, and that’s something every driver can appreciate. Plus, the increased eccentricity helps combat bore distortion at high RPMs, making sure the hydrodynamic oil films form just right.

Now, let’s talk specifics. The 3/4 grooved main bearings are designed to optimize the load-carrying surface area and ensure oil flows smoothly to the conrod bearings. Consistent wall tolerances mean you can maintain those clearances without any guesswork, which is crucial when you’re tuning for performance. And if you’re working with performance crankshafts, you’ll appreciate the enlarged ID chamfers on the bearing edges—they accommodate those larger fillet radii perfectly.

In terms of fitment, these bearings cover a range of popular applications. You’ll find them suitable for models like the Mazda 3 (2004-2021) and Mazda 6 (2003-2018), along with the Mazda Tribute (2001-2006 & 2008-2011). It’s a solid choice for anyone looking to upgrade their engine’s performance.

Here’s a quick rundown of the specs:

• Sizes available: STD, .025, .25
• Oil Clearance: Standard
• Half Type: Identical Halves
• Material: Tri-metal Hardened Steel Backs
• Min Std Shaft Size: 2.0465" / 51.980 mm
• Max Std Shaft Size: 2.0472" / 52.000 mm
• Min Std Tunnel Size: 2.1662" / 55.021 mm
• Max Std Tunnel Size: 2.1667" / 55.034 mm
• Max Wall at Crown: 0.091" / 1.500 mm
• Max Overall Length: 0.669" / 17.00 mm

So if you’re looking to boost your engine’s performance and reliability, these ACL Race Series Engine Bearings are definitely worth considering. They’ve got the specs and the build quality that serious drivers need, and from my experience, they deliver on their promises.