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New Mopar Street and Crate Hemis
(426 and 572 Hemi blocks)


After production of the street Hemi® stopped in 1971, enthusiasts were faced with a limited supply of Hemi parts. Direct Connection (now Mopar Performance) and aftermarket vendors helped, but blocks and heads became rarer as time went on. The musclecar collecting craze sent Hemi prices through the roof, buyers of used parts had to be wary. Racers also had to deal with the possibility of violating NHRA specs as blocks wore and numerous valve jobs sunk the heads deeper into the combustion chambers.

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Starting in late 1992, Mopar Performance began making new 426 Hemi blocks, moving on to heads, pistons, and other parts, making it possible to build a new 426 Hemi. The new block had the same outward appearance as the original (except for a new casting number), with a thicker deck for better stiffness and gasket sealing; the improved rigidity brought around 25 extra horsepower. Mopar Performance also made a version with B/RB engine mounts, so a Hemi could be dropped into a big block car without a Hemi K-member. The heads had hardened valve seats to allow unleaded fuel; in later years, Mopar added a single 4-bbl manifold, and a magnesium supercharger manifold for top fuel racing.

A Short List of Key 1990s 426 Hemi Part Numbers:
P4529850 Cast Iron 426 Street Hemi Block
P4529852 Cast Iron 426 Street Hemi Block w/ B/RB motor mount ears
P4529898Cast Iron Street Hemi Head

P5249524
Cast Iron Dual Plug Street Hemi Head

P5249525
Cast Iron Street Hemi Head w/ hardened valve seats

P5249206
Resto Crankshaft (others available)

P5249436-37
10.25:1 cr. Hemi Pistons (others available)

P4529315-6
Original Equipment Hydraulic and Mechanical Camshafts

The second-generation Hemi 99, designated DPS2, was launched in 2006. Created by Chrysler using CATIA, the new engine had a compacted graphite iron block, with higher efficiency; it was developed by Bruce Phillips and David James. This was a Pro Stock motor producing roughly 1,400 horsepower; the NHRA and Bob Glidden were both consulted.

Aluminum 426 Hemi Crate Engine (2014)

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The 426 Hemi Generation III crate engine produces 600 horsepower and 590 lb-ft of torque, with an aluminum block, pistons, and heads; it has a forged steel crank and rods, billet steel main caps, and a hydraulic roller cam (0.639" lift). Fuel is delivered via multiple-port injection. There are also 515 and 565 horsepower versions, with 490 and 550 lb-ft of torque, respectively. The torque curve is remarkably flat.

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2014 572 Hemi Crate Engine

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The 572 Hemi Generation II crate engine uses a heavy-duty siamese-bore cast iron block with cross-bolted mains, aluminum heads with 2.25" intake valves and 1.94" exhaust valves, and an aluminum single-plane intake for one carburetor (an optional cross-ram intake for dual carburetors is shown in the photo). The camshaft is hydraulic, with flat tappets; the engine has a 10.0:1 compression ratio. As equipped, it produces 650 hp, with 660 lb-ft of torque. There are black and orange valve cover options (orange is shown).

572-hemi.jpg


Return to Hemi Central392 Hemi Crate Engine (2006)

This page created by Steve Boelhouwer and updated in 2014 by the Allpar staff to reflect changes since 1998



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