Building a Hemi for Less - Build A Budget Hemi

The Stage V Engineering Hemi Conversion heads share all critical details with Chrysler 426 Hemi heads but are cast to accommodate the specific oiling, head bolt, and pushrod placement features of the wedge block. They're sold minus valves and springs but do include conversion-specific rocker arms, shafts, and stands. We fleshed them out with Manley valves, springs, cups, retainers, and locks. Spring pressure is 205 pounds on the seat and 560 pounds at 0.688 lift to suit our solid roller cam.

The Stage V Engineering Hemi Conversion heads share all critical details with Chrysler 426

Whether you're a lifelong Mopar fanatic, a recent convert, or just a guy who knows an excellent engine when he sees one, you want a Hemi. Fortunately, there are numerous ways to scratch the itch, the most cost-effective being a preassembled 426 Hemi crate engine from Mopar Performance. Listed as PN P5249667AC and selling for about $13,500 on the open market, the Mopar Performance 426 Hemi crate makes 465 hp and 485 lb-ft. By most accounts, it's the least expensive Hemi strategy on the planet. Or is it?

What if we told you-for a couple hundred bucks less-you could get a whole lot more? How 'bout 520 cubes, billet internal parts, and 684 hp and 625 lb-ft on 91-octane unleaded pump gas? It's true. The plan centers on a set of very special aluminum Hemi heads designed and manufactured by Stage V Engineering. Known as Hemi Conversion heads, you put 'em on a common-as-dirt 440-Wedge block and-with a matched piston, camshaft, and induction swap-the end result is a wedge that looks and runs like a big 'ol honkin' Hemi.

Compare the wedge head gasket (top) with the Hemi head gasket (finger points) and you can see where the wedge block is rounded off versus the square deck ends found on Hemi blocks. This is where oil-drain-back holes are found on Hemis. The Hemi Conversion heads are cast without drain-back passages and use external drain hoses instead. The center row of head-bolt holes in the block must be up-sized from 7/16 to 1/2 inch for better gasket clamp and compatibility with the Stage V rocker-shaft stands.

Compare the wedge head gasket (top) with the Hemi head gasket (finger points) and you can

No, the two-bolt 440-Wedge doesn't offer the cross-bolted main caps and extra beef of the 426 Hemi block, but with minor preparation-and expert machine work-the wedge block will safely handle up to 750 hp. Aside from the main cap situation, the Hemi Conversion strategy outlined here is all gravy versus the original 426. The perks include billet crank and rods instead of forged steel, aluminum heads instead of cast iron, 520 cubes instead of 426, dual quads on a Street Hemi manifold instead of the 426 crate's single quad, roller rocker arms instead of scrubbers, leak-free cast-aluminum rocker covers instead of stamped tin, a healthy, solid roller cam instead of a hydraulic flat tappet, 113 pounds less weight (607 pounds versus 720 pounds fully assembled), and the peace of mind that you-or your engine builder-put it all together.

Check out the pictures and follow along as Joe Jill and the crew at Superior Automotive bolt together a 520-cube Hemi Conversion motor that goes several steps beyond the original 426 Hemi-for similar money.

Stroker Hemi Conversion Ingredients And Price ListDisplacement: 520 ciHorsepower: 684.6 hp at 6,300 rpmTorque: 625.7 lb-ft at 4,600 rpmCompression ratio: 9.8:1Ignition timing: 34 degrees BTDCBore/stroke: 4.350x4.375Bore/stroke ratio: 0.994:1Rod/stroke ratio: 1.55:1Maximum safe engine speed: 7,000 rpmRecommended shift point: 6,500 rpmCost to build: $13,355.32

Because domed Hemi pistons are heavier than wedge pistons, you really need to splurge on good rods. For the sake of comparison, the standard 440 forging on the left (840 grams) is marginal at these power and rpm levels. The middle rod is a Six Pack forging (882 grams). Its wider beam adds strength, making it slightly more durable. We're going way beyond, so we used premium Crower 4340 lightweight billet rods (869 grams). The 2.20-diameter big end is smaller-and lighter-than Chrysler's 2.375 for a compact package that'll handle up to 1,000 hp. All rods measure 6.770 center to center.

Because domed Hemi pistons are heavier than wedge pistons, you really need to splurge on g

The head gaskets are standard-issue 440 by Fel-Pro with a 0.039 compressed thickness but must be nibbled for pushrod clearance on the workbench using a circular punch. If you don't have the time, Stage V Engineering sells pre-punched gaskets.

The head gaskets are standard-issue 440 by Fel-Pro with a 0.039 compressed thickness but m

All buttoned up, Joe Jill Jr. (left) and Don Spaccarotella set timing to 34 degrees on the Superior DTS dyno. With a pair of 1404 Edelbrock Performer 500-cfm carbs on the intake and exhaling through a set of cast-iron Street Hemi manifolds, it delivered 612.9 hp at 6,100 rpm and 569.7 lb-ft at 5,300 rpm. But we're not done . Replacing the Street Hemi manifolds with TTI 21/8 dyno headers, output jumped to 661 hp at 6,100 rpm and 600 lb-ft at 4,600 rpm. That's a sweet gain of 48 hp and 30 lb-ft. Thanks go to Kenn Funk for the loaned manifolds.

All buttoned up, Joe Jill Jr. (left) and Don Spaccarotella set timing to 34 degrees on the

With a stump pulling 587 lb-ft way down at 3,500 rpm and peak horsepower reached at a conservative 6,300 rpm, the benefits of the stroker crank and free-flowing heads are clear. We made more than 15 dyno pulls to ensure repeatability, and every one was made with 91-octane Shell gasoline from a local station.

This motor makes peak power at 6,300 rpm and rarely exceeds 6,500 rpm, so the stock-type fixed internal pickup and deep-sump oil pan are completely adequate. Assemblies that exceed 6,500 rpm on a regular basis should be fitted with external oiling systems for added safety. Also offered by Milodon, the external oiling strategy bypasses the restrictive drilled block passages with free-flowing hoses and fittings. >>>>>>