Eagle rotating assemblies can take a lot of worry out of your engine building project. Combinations are the key, it has been said. Eagle provides multiple choices for popular engine rotating assembly combinations to fit almost any application. With an Eagle assembly, you take the guesswork out of selecting bottom end components. Eagle rotating assemblies are test-fitted in house to ensure everything works well together. We offer a wide range of compression ratios, bore sizes from many different piston manufacturers such as Federal Mogul / Speed Pro, KB, Icon, Mahle, JE/SRP, CP/Arias, Traum, Diamond, DSS, and Ross. At the entry-level, we offer our "Street & Strip" rotating assemblies that feature our cast crankshaft, forged 5140 steel I-Beam rods, and either hypereutectic or forged pistons. These are recommended for pump-gas, street vehicles. No power adders, slicks, or competition use! The next step up is our "Pro Street" assemblies. Pro Street kits feature our forged 4140 steel crankshaft, forged 4340 I-Beam rods, and either hypereutectic or forged pistons. Pro Street assemblies are intended for naturally-aspirated competition use. The majority of the assemblies we offer are our original competition assemblies. Competition assemblies feature our forged 4340 steel crankshaft, 4340 steel H-Beam rods and only forged pistons. Competition assemblies are recommended for use in most competition engines. Boost, exotic fuels, nitrous? A Competition assembly is what you need! For the really over-the-top engine builds, Eagle offers our Heavy-Duty assemblies. Sorry we didn't come up with a catchy name, but these assemblies are all business. Equipped with our forged 4340 center-counterweighted crank (when available), forged H-Beam rods with ARP 2000 or L19 bolt upgrade and purpose-built heavy duty pistons. The pistons used in Heavy-Duty assemblies are built for high boost levels or bucket-loads of nitrous. Every part is top-of-the-line and ready to support whatever you want to throw at it. Most all assemblies are available balanced or unbalanced if you'd rather your machine shop balance it. Along with crank, rods, pistons, every assembly includes bearings from either King or Clevite and rings suited to the intended application. Externally balanced assemblies balanced by Eagle will also include a harmonic damper and flexplate (or flywheel for some Fords) from Pioneer.