Hemify Your Wedge

No matter what your automotive persuasion, there's no denying the magical allure of the Chrysler Hemi. And with Madison Avenue going ga-ga over the H-word these days, maybe its time you answered "yes" the next time somebody asks; "That thing got a Hemi in it?" We can hear you whine; "But they're sooooo expensive." Well yes and no. Thanks to Stage V Engineering (SVE), you can base your next Hemi project on a common 440 wedge block, saving thousands of bucks, and nearly 100 pounds, over a traditional cross bolted Hemi bottom end. And with basic preparation, the 2-bolt 440 bottom end can handle as much as 800 horsepower. Best of all, with the bucks saved you can step up to some serious cubic inches, courtesy of a 5/8-inch stroker crank with Chevy Rat motor big end dimensions.

HEMI STROKER CUBES
With a whopping 520 cubes of displacement, the SVE Hemi conversion motor outlined here out-guns many of the popular crate Hemis but costs way less. Better still, thanks to the lighter wedge block and aluminum heads, it tips the scales at only 607 pounds complete, has a conservative 9.8:1 compression ratio for 91octane pump gas friendliness and hardened intake and exhaust valve seats so you can beat on it to your heart's content with unleaded fuel. We sure do.This one is bolted into a 1967 Dart that weighs 3,400 pounds, makes 600 horsepower (501 horsepower at the tires), runs 10.99's at 127 on 10-inch slicks and 4.10 gears, yet cruises comfortably in any traffic situation Southern California can dish out. So far it's got over 5,000 miles of trouble free street and strip action.

Though SVE doesn't sell complete engines like some outfits of late, when you buy their Hemi conversion kit, you get two fully assembled aluminum heads with all the required valve train parts that are ready to bolt on to the short block of your making. This way you can be certain of the quality and craftsmanship because you (or your machine shop) built it yourself.

Since they began selling Hemi conversion kits in 1987, SVE has accumulated an extensive knowledge base of what works best and supplies every customer with a complete recipe that eliminates mystery while ensuring the finished engine hauls butt. The wedge-to-Hemi conversion process requires Hemi-specific pistons, a Hemi-specific camshaft, Hemi pushrods, Hemi valve covers and Hemi exhaust, but once the wedge block is Hemi-ized, any Hemi style factory induction setup bolts right on. Lets watch as Dale Reed, proprietor of Dale's Place, in Baldwin Park, CA, puts one together.

Any 1966-'78 440-block is...        read full caption Any 1966-'78 440-block is an excellent Hemi conversion candidate though pre-'75 castings are generally thicker and stronger. Ours is from a 1969 Chrysler Newport. Part of the attraction is the fact that, at 213 pounds, the 440- block is about 70 pounds lighter than a Hemi-block.

Though lacking the Hemi's...        read full caption Though lacking the Hemi's cross-bolted main cap configuration, the two-bolt wedge bottom end can be upgraded to withstand 800 horsepower by enlarging the stock 1/2-inch bolt holes to accept larger ARP 9/16-inch studs at the 2, 3 and 4 positions. The 1 and 5 positions remain 1/2-inch but, ARP studs (torqued to 100 lb-ft) replace the stock bolts. All drilling operations must be done by a competent machinist to preserve dimensional accuracy. For enhanced oil delivery, the main bearing feed holes are enlarged to 9/32-inch on number 2 and 3, and 5/16-inch on number 4.

The center row of head bolts...        read full caption The center row of head bolts must be enlarged from 7/16 to 1/2-inch to assure maximum head gasket seal. SVE offers a Grade 9 head bolt kit or head studs could be used.

Pushrod clearance must be...        read full caption Pushrod clearance must be ground into the wedge's lifter valley because of the Hemi conversion's different push rod angles. The clearance reliefs are 1/8-inch deep and can be done by hand with a die grinder.

Here's a look at the pushrod...        read full caption Here's a look at the pushrod clearance reliefs after grinding. Note that SVE offers pre-notched Fel-Pro head gaskets that can be used as grinding templates.

With the money saved on the...        read full caption With the money saved on the block, we splurged on a serious displacement boost with an ex-Top Alcohol 4340 billet steel crank with 4.375-inch stroke. This is a 0.625-inch (5/8-inch) increase over the stock Chrysler 3.75-inch stroke and yields a nasty 520 cubic inches with our 0.030 oversize, 4.350-inch pistons. The rod journals were reduced to 2.200-inch big-block Chevy diameter, which virtually eliminates the extensive crankcase clearancing required in stroker Chryslers. Chrysler-length (6.770-inch) lightweight 4340 steel rods from Crower and Arias pistons give a lighter bob weight of 2,471 grams (stock 426 Hemi is 3,095 grams). The result is a 520ci Hemi that revs like a small-block!

Thanks to the reduced Chevy...        read full caption Thanks to the reduced Chevy rod journal dimensions the only clearance work required is a small notch on the oil pickup tube boss. Also, the tube is moved away from the reciprocating assembly by offset drilling the stock 3/8-inch diameter pickup tube hole to 1/2-inch. SVE designed a special fixture for this modification. No windage tray is used. The simple, but effective Milodon oiling system consists of a 1/2-inch pickup tube, 7-quart pan, and high volume oil pump.

Arias 9.8:1 high silicon forged...        read full caption Arias 9.8:1 high silicon forged pistons weigh 724g and have generous valve relief notches. The increased silicon content minimizes thermal expansion so tighter 0.006-inch skirt clearance can be used for better oil control and piston life on this street engine. The ring package is from Speed Pro and uses 1/16-inch chrome-moly top rings (0.018-inch end gap), 1/16-inch iron second rings (0.014-inch end gap), and 3/16-inch oil scrapers.

When the wedge block is fitted...        read full caption When the wedge block is fitted with SVE Hemi conversion heads, a Hemi specific camshaft must be used due to the different port layout. Our cam is a Crower roller with 0.626/0.631-inch lift and 298/304 advertised duration. Crower solid roller lifters, push rods, thrust button, and a Cloyes Tru-Roller timing set move the valves.

The aluminum SVE Hemi conversion...        read full caption The aluminum SVE Hemi conversion heads look just like 426 parts but feature revised head bolt holes and specific oil and coolant passages to suit the needs of the wedge block. They are specifically cast for wedges and do not fit Hemis. We filled our heads with Manley 2.20/1.90-inch stainless valves, double valve springs, spring cups, 10-degree locks lash caps and titanium retainers.

Fully assembled, the heads...        read full caption Fully assembled, the heads weigh 38-pounds each, a full 26-pounds less than iron Hemi heads. This 52-pound savings plus the 70-pound lighter wedge block drop the total weight of this 520-inch conversion motor to 607 pounds versus 730 of an iron 426. To accommodate the shape of the wedge block's lifter valley and get needed exhaust pushrod clearance, SVE moves the exhaust rocker arms 1/2-inch closer to the center of the block via specific extruded aluminum rocker shaft stands. These heads also require special cast stainless steel roller rocker arms that are1/2-inch longer than stock 426 parts. The conversion kit also comes with cast stainless steel roller intake rocker arms.

Once the conversion heads...        read full caption Once the conversion heads are bolted down, the wedge thinks it's a Hemi and accepts any stock-type (16 bolt) intake manifold. White grease aids gasket seal while a dab of RTV applied to the borders of the cork end seals prevents messy oil seepage.

To remedy the wedge block's...        read full caption To remedy the wedge block's lack of suitable oil return architecture, conversion motors rely on external oil drain back plumbing. Braided AN hoses and fittings at rear corners of the engine empty into the crankcase via 3/8-NPT holes drilled and tapped into the block.

A pair of 750-cfm Edelbrock...        read full caption A pair of 750-cfm Edelbrock Performer carburetors feed our Hemi conversion mill for excellent street/strip flexibility. On our 1966 Street Hemi manifold, half of the plenum area below each carburetor had to be milled out to clear the 1-11/16 throttle plates. Joe Jill at Superior Automotive (714/894-9711) handled the task.

At home under the hood of...        read full caption At home under the hood of a '67 Dart, it's hard to imagine this Hemi has the heart of a Wedge. The cast aluminum rocker covers are from SVE. Also any late Hemi rocker covers fit.

For those who want improved...        read full caption For those who want improved performance and greater tuning options, try the new SVE Rat Buster single plane intake and a set of short-bowl equipped Holley 750's. With no other changes, output at the rear wheels jumped from 501 to 524 horsepower.