If you're looking to push your engine to the limits, the ACL Race Series Engine Bearings are definitely worth considering. These bearings are crafted for those who demand high performance, especially in 4, 6, and 8 cylinder setups. They’re designed to handle the high RPMs that come with serious driving, so you know they’re built tough.

What sets these bearings apart? For starters, the high strength overlay plate is thinner than what you’d typically find, which not only helps with fatigue resistance but also keeps your engine running smoother under pressure. The hardened steel backs on all rod bearings provide solid support for the lining, ensuring everything stays put even when the engine's roaring.

One of the standout features is the increased crush, which enhances bearing retention. This means you won’t have to worry about your bearings slipping out of place when you're pushing your car hard. They’ve also eliminated flash plating on the back of the bearings, which does wonders for heat transfer. Better heat management means more reliable performance, especially when you're really pushing your engine.

These bearings have increased eccentricity too, which is a fancy way of saying they’re designed to handle bore distortion at high RPMs. This helps create those all-important hydrodynamic oil films that keep everything lubricated and running smoothly. And let’s not forget the 3/4 grooved main bearings—they optimize the load-carrying surface area and ensure that oil flows efficiently to the conrod bearings, which is crucial for performance.

When it comes to fit, these bearings have tight, consistent wall tolerances that help maintain your clearances. Plus, the enlarged ID chamfers on the edges accommodate larger fillet radii on performance crankshafts, which is a nice touch for those of us who like to tweak our setups.

In terms of specs, you’ve got options for sizes like STD, .025, and .25, with standard oil clearance and identical halves. The material is tri-metal with hardened steel backs, ensuring durability. For the nitty-gritty details, the minimum standard shaft size is 1.888 inches, and it goes up to 1.8887 inches at the max. The tunnel sizes range from 2.0079 to 2.0084 inches, and the max wall at crown is 0.0592 inches. Overall, they measure in at 0.6732 inches in length.

So if you’re working on a Nissan RB25DETT or RB26DETT, this ACL Rod Bearing Set is definitely worth a look. It’s all about performance, reliability, and getting the most out of your engine without compromising on quality.