Eagle H-Beam rods are a high-end performance connecting rod. We are currently under our 3rd major design iteration, hence the "3D" name for 3rd Design. We have made minor improvements to this base design over the years. It is likely that the rods we offered 5 years ago are not the same that we are selling now! Eagle did not invent the H-Beam rod. To the best of our knowledge, the first appearance of the H-Beam design was in World War 2 when the addition of nitrous to fighter planes caused the I-Beam rods in their engines to fail. The H-Beam rod was invented and used to handle the increased stress. We forge our H-Beam rods from premium 4340 steel in a 2-piece forging. The beam part of the rod is forged seperately from the cap part. While it is a minor detail, the cap is forged perpendicular to the beam because that is the direction best suited to handle the loads the cap sees. This results in an improvement is bore size stability under high loads. To our knowledge, no other rod manufacturer does this. Our rod forgings are X-ray inspected to ensure there are no impurities or inconsistencies. They are also randomly spot-checked to ensure alloy consistency so that you know you are getting the best material money can buy for high-strength connecting rods. While the rod is suitable for very high-power applications, the bolts needed to match the rod's capabilities can be expensive, and honestly are overkill for what a lot of racers need. To realize the full potential of Eagle H-Beam rods, ARP L19 or Custom Age 625+ bolts are needed. We have seen big blocks reach 1700hp, turbocharged 4 cylinders make over 1300hp with our H-Beam rods and top-of-the-line bolts. To help reduce costs, Eagle H-Beam rods are sold with ARP 8740 bolts standard (V8s). These are recommended for use up to 800 hp. The next step up is ARP 2000 bolts (standard on 4 cylinders, some 6 cylinders, and optional on V8s). These are recommended up to 900hp on turbocharged 4 clyinder engines, 1500hp on turbocharged 6 cylinder engines and 1300hp on V8s - any way you make it. Turbocharged V8s have pushed these bolts much higher than 1300hp, though. The strongest option currently availble for V8 applications is the ARP L19 bolt. We have seen nitrous and supercharged applications push these over 1700hp. Turbocharged V8s, close to 2000hp. For sport compact applications with a 3/8" bolt, the best bolt is the ARP custom Age 625+ bolt featured in our Extreme Duty version of these rods. We have had a difficult time putting a power rating on these as we just haven't had any fail yet. We've seen close to 1300hp from them in a 4 cylinder. They are not indestructable. There is a limit - we just haven't found it yet. We feel 1300hp (or 900hp, really) will suit almost any realistic racer's expectations. All Eagle H-Beam rods are bushed for full-floating piston pins, with one exception. The Pontiac rods are available either bushed or press-fit. Alignment sleeves are used to precisely position the cap. The H-Beam design features a fully-machined surface that is shot-peened so there are significantly fewer microscopic inclusions on the surface than an as-forged rod. This improves fatigue life dramatically because those inclusions are where fatigue cracks begin. To further perfect the surface and completely remove all inclusions, a variation of our ESP Armor process is used when producing our Extreme Duty rods. Because these rods are commonly used in stroker applications, attention has been paid to the are of the rod that would contact the cam in Chevy small block applications so that adequate cam clearance should exist without the need for a small base-circle cam. While it is impossible to test-fit every cam that exists, it is always best to confirm you have at least .050" clearance between the cam and the connecting rod. For Chevy small-block application of 3.875" stroke and longer, we offer rods with additional clearancing to help with cam clearance. These are our "Extreme Stroker" connecting rods. Eagle H-Beam rods are recommended for use in competition engines including those utilizing exotic fuels, forced induction, and nitrous. Pay attention to what bolts you order your rods with! If you need help, please call us and we help recommend what's right for your engine. Eagle H-Beam rods are not legal for use in pollution-controlled vehicles.