The Iron Eagle has a revised oiling system that feeds the mains before the lifters, and the galley plugs are different from a stocker's; a Dart Parts hardware kit is included. The Dart block can be ordered with larger-diameter big-block cam bearings to allow for larger-base-circle cams (to make them stiffer for extreme-valvespring race applications), but this one has regular small-block bearings. However, all Dart small-blocks use five cam bearings of the same o.d., whereas stock Chevy bearings get progressively smaller. A special bearing set is included with the block, but not the rear cam plug, which is a 2.375-inch Ford FE type.The Iron Eagle has a revised oiling system that feeds the mains before the lifters, and th We know of no budget-priced, 4.125-inch-stroke small-block cranks, but Lunati's Pro Series (PN AU211EN) sells for under $1,500. The crank is a 4340 non-twist steel forging with Lunati's Contoured Wing counterweights designed to direct windage away from the rods to improve power. The crank uses large, 2.65-inch, Chevy 400-style main journals (instead of 2.45-inch 350 mains) to improve the overlap of the crank journal to the rod journal to add strength with the long stroke. Dougan's was able to internally balance the assembly, but two small slugs of Mallory were needed.We know of no budget-priced, 4.125-inch-stroke small-block cranks, but Lunati's Pro Series We used Lunati 4340 forged-steel Pro Mod rods (PN LAE1) in a 6.125-inch length (stock 350 Chevy is 5.700 inch). The 1/16-, 1/16-, 3/16-inch piston rings are Speed Pro Hellfire units file-fit to end gaps of 0.020/0.018/0.024. All the bearings are also Speed Pro chamfered race units to match the full-radius journals on the crank. Clearances are 0.0022 to 0.0025 on the rods and 0.0027 to 0.0032 for the mains.We used Lunati 4340 forged-steel Pro Mod rods (PN LAE1) in a 6.125-inch length (stock 350 The piston position at BDC reveals two things. First, that the long connecting rods are needed to prevent piston-skirt-to-crank-counterweight contact with the long stroke. Second, that the tall deck height of the block is required to accept the combination of stroke and rod length. This combo would stick out the top of a stock Chevy block by about 516 inch. Dougan's measured the overall length of a stock Chevy cylinder as 5.750 inches at a 9.025-inch deck height; the Dart cylinders are longer at 5.8925 at a 9.325 deck height.The piston position at BDC reveals two things. First, that the long connecting rods are ne Even with the Iron Eagle casting, a bit of grinding was needed (arrows) for clearance with the somewhat large big-end of the Lunati rods. However, cam-to-connecting-rod clearance was ample with the raised-cam block. Even on a common 383ci stroker with a 3.75-inch crank, interference from the inside connecting rod bolts to the camshaft lobes is very typical with a stock block.Even with the Iron Eagle casting, a bit of grinding was needed (arrows) for clearance with Moroso sells two versions of a 7-quart steel oil pan designed for Iron Eagle blocks, and they are both rear-sump and should clear your front axle. We used PN 20193 which includes an integral one-way trap door, crank scraper, and windage tray; PN 20192 is the same without the scraper and tray. We also used a Moroso pickup and PN 22100 oil pump. For the harmonic balancer we chose the largest-diameter neutral-balance TCI Rattler available (PN 870002).Moroso sells two versions of a 7-quart steel oil pan designed for Iron Eagle blocks, and t Iron Eagle: Secret to Big CubesThe idea of a big-inch small-block first hit us about 10 years ago when GM introduced the Rocket Block, an Olds-branded casting designed specifically for long strokes by incorporating a raised camshaft location and 0.800-inch-wider-than-stock oil-pan rails. The Rocket was also available with a deck height (crank centerline to deck surface) of 9.325 inches, 0.300 taller than the blueprint spec of a stock Chevy block. The taller deck height allowed for longer connecting rods and/or a taller piston compression height than would otherwise be practical with a very long stroke. When the Rocket Block was new, its special features demanded a bunch of fabricated parts that made the engine impractical for a backyard wrench to assemble or afford. Then GM discontinued the Rocket. Today, Dart offers the Iron Eagle small-block casting with all the benefits of the Rocket block, and several aftermarket companies have the parts needed to easily slam together a big-inch small-block. If you're considering the price of an engine built with a stock block and China-made budget crank and rods, then the Dart 450-incher will be way more expensive. But if you compare the prices of the custom Iron Eagle parts with conventional-style components of the same top quality that we used in this buildup, then going big will run you about an extra $500. Here's the list of all the special parts you'll need for an Iron Eagle block compared to a standard block, plus the part numbers of the specific components we used. *Spread-rail oil pan (Moroso PN 20193)*Raised-cam timing set (Comp Hi-Tech PN 3146KT)*Longer, big-block-style oil-pump driveshaft (ARP 135-7901)*Big-block-style fuel-pump pushrod (ARP 135-8701)*Intake-manifold spacers (Dart PN 622100002)*Remote oil filter (Moroso Omni Filter PN 22285)*Slip-collar-style distributor (MSD PN 85561)*Line-bored-400-Chevy-style rear main seal (Fel-Pro 2909) *2.375-inch, Ford FE-style rear cam plug « | 1 | 2 | 3 | 4 | » | View Full Article By David Freiburger Enjoyed this Post? Subscribe to our RSS Feed, or use your favorite social media to recommend us to friends and colleagues!