Hands On We should probably clarify this article's headline right away. By hemi power, we mean factory-rated horsepower for something like a '68 Hemi Roadrunner, and by half the cost, well, that's self-explanatory. The relatively low cost is why this build is running in this issue. Brian Hafliger of IMM Engine and Dyno was able to take a lowly 400 block and piece it together with a clever combination of used factory parts, some good machining, and a mild aftermarket cam kit, and make as much factory-rated horsepower as the mighty Dodge and Plymouth 426 Hemi engines in '66 through '71 Dodge and Plymouth cars. Best of all, aside from the machining, this engine can be built at home. There were no exotic parts in this engine, and no black-magic porting was done to the cylinder heads or intake manifold. Mopar fans, start scrounging eBay or your local swap meets and salvage yards. Grab yourselves a 400, and make some power. On the Dyno We were honestly surprised by the power this combination made. None of the random guesses from the peanut gallery crowding around IMM's dyno cell were this high. Brian and his dad were hoping for about 415 hp, but everyone else guessed lower than that. All eyes widened as the horsepower figures crested 415 on the very first pull. After just minor tweaking to the carburetor jetting and advancing the timing by 2 degrees, we achieved a peak horsepower number of 426.7 at 5,700 rpm, the same as what the 426 Hemi in Roadrunners and Chargers were rated at. There may actually be a few more ponies lurking inside this engine, but Brian didn't feel comfortable pushing the engine too much farther. The weak links in this combination are the OE-style rocker arms, which weren't designed for the spring pressures and engine speed we were asking of them. If you are looking to replicate this build but have a little more money to spend, consider a rocker-arm upgrade. Otherwise, this is an engine you could drop into a classic Mopar and surprise a few people with the power you're getting from what was never really considered to be a performance engine. *Note: These are IMM's prices. Your local machine shop's costs will vary. Manufactured throughout the '70s, Chrylser's 400 is a larger-bore variant of the 383. Technically, both the 383 and 400 are B engines, having a lower deck height than the RB blocks (9.980-inch versus 10.725). The 400 is hugely oversquare with a large 4.342-inch bore and a tiny 3.38-inch stroke, shorter than a 350-inch small-block Chevy. That big bore size helps the engine breathe, because the cylinder walls do not shroud the intake and exhaust valves, making this block an interesting choice for a potentially high-rpm powerplant or an ideal candidate for a stroker crankshaft.Manufactured throughout the '70s, Chrylser's 400 is a larger-bore variant of the 383. Tech We stuck to the basics for this build. Brian found a used 383 crankshaft and bolted it in. While the 383 and 400 crankshafts have the same stroke, many 383s had forged cranks, while 400s rarely did.We stuck to the basics for this build. Brian found a used 383 crankshaft and bolted it in. The connecting rods are stock 400 parts. Hafliger resized the rods after installing ARP rod bolts. He reused the stock main bolts so he wouldn't have to align-bore the main caps, but he did bore the block 0.030-inch over and installed off-the-shelf pistons.The connecting rods are stock 400 parts. Hafliger resized the rods after installing ARP ro Highly recommended is 440 Source's billet aluminum rear main cap. "They hold the rear main seal better. We've never had an oil leak when we used one of these," says Hafliger.Highly recommended is 440 Source's billet aluminum rear main cap. "They hold the rear main Typical of the era, these were low-compression engines, and the decks weren't square when he first mocked up the engine. Hafliger milled the block 0.027 inch on one side and 0.019 from the other to square the block and set the pistons to zero deck. The pistons and their corresponding 5/64-inch rings weigh a hefty 856 grams.Typical of the era, these were low-compression engines, and the decks weren't square when Prior to the valve job, Brian cleaned the bowl area of the combustion chambers. This is work that any competent machine shop could do, and it would not be considered porting. Other than smoothing the transition from the ports to the seats, no other work was done to the cylinder heads.Prior to the valve job, Brian cleaned the bowl area of the combustion chambers. This is wo Hafliger also milled the cylinder heads 0.050 inch to reach his goal of a 9.8:1 compression ratio. Unlike open-chamber big-block Chevy heads, these 906 castings (popular on 440 engines) have shallower, 86cc combustion chambers. Milling the heads brought the volume down to 79 cc. He replaced the original valves with Manley parts of the stock diameter (2.07-inch intake, 1.74-inch exhaust). He performed a standard, three-angle valve job and a 20-degree back cut on the intake valves before installing them.Hafliger also milled the cylinder heads 0.050 inch to reach his goal of a 9.8:1 compressio We chose Comp's Thumpr cam kit, which includes the cam, the timing set, lifters, valve springs, retainers, locks, and seals—a lot of stuff for $500. The cam specs are 227/241 degrees duration at 0.050 with 0.486/0.473 valve lift with 1.5:1 rocker arms and a 107-degree lobe-separation angle. Hafliger installed the cam straight up.We chose Comp's Thumpr cam kit, which includes the cam, the timing set, lifters, valve spr To save some money, we decided to reuse the factory shaft-mount rocker arms. These aren't strong parts and are notorious for shooting pushrods out through the rocker at high rpm or with heavy valvesprings. However, they survived this engine's 5,700-rpm dyno pulls.To save some money, we decided to reuse the factory shaft-mount rocker arms. These aren't B-SERIES ENGINES, BY THE NUMBERS 383 400 BORE 4.250 4.342 STROKE3.3803.380 DECK HEIGHT9.9809.980 FIRING ORDER1-8-4-3-6-5-7-21-8-4-3-6-5-7-2 DISTRIBUTOR ROTATIONclockwiseclockwise On the Dyno RPM HP TQ 3000233407 3100244412 3200253414 3300260415 3400269416 3500280419 3600289423 3700299424 3800310429 3900322433 4000335439 4100346443 4200355444 4300363442 4400370441 4500378440 4600385438 4700390435 4800395430 4900402431 5000409430 5100416427 5200420424 5300421417 5400422409 5500420401 5600422396 5700426393 PARTS LIST DESCRIPTION PN SOURCE PRICE Used 400 block NA Salvage yard $300.00 Used 383 forged crankshaft NA IMM Engines 200.00 Used 906 casting cylinder heads, complete NA eBay 125.00 Head gaskets FEL-1009 IMM Engines 87.95 Main bearings409M IMM Engines 64.99 Rod bearings 8-2320CP IMM Engines 67.99 Durabond cam bearings PDP-17-T IMM Engines 54.95 Engine bolt kit ARP-545-9701 ARP 148.87 Pistons UEM-KB240-030 Summit Racing 446.82 Thumpr cam and lifter kit K21-600-5 Comp Cams 499.95 Manley pushrods, qty. 16 MAN-25447-1 Summit Racing 271.20 Harmonic balancer PB1112-ST IMM Engines 160.00 Oil pump MEL-63HV Summit Racing 69.95 Oil-pump driveshaft MEL-IS-63 Summit Racing 41.95 Billet rear main seal cap 200-1031 440 Source 39.95 Chrylser B-body oil pan 121-1001 440 Source 59.95 Oil-pump pickup 101-1010 440 Source 34.95 Engine Break-in oil CCA-1590 Comp Cams 59.95 Distributor MSD-8386 MSD 379.95 Street Fire plug wires MSD-5562 MSD 38.95 Autolite 86 spark plugs, qty. 8 FRM-86 IMM Engines 12.00 Headers TTI383-178C4 TTI Exhaust 866.00 Performer RPM intake manifold EDL-7193 Edelbrock 209.95 Holley 750 Double Pumper Carburetor HLY-0-4779C Summit Racing 439.95 Valley pan and gaskets FEL-1214 IMM Engines 24.75 Valve covers EDL-4493 Edelbrock 51.95 Total$4,757.87 LABOR DESCRIPTION PRICE Hot tank block$45.00 Install cam bearings50.00 Install freeze plugs and oil gallery plugs50.00 Mock-up for zero decking60.00 Resurface block125.00 Bore and hone with torque plates250.00 Mill cylinder heads120.00 3-angle valve job160.00 Resize rods100.00 Polish crankshaft95.00 Balance crankshaft175.00 Press fi t wrist pins55.00 Mill intake manifold125.00 Total$1,410.00 The intake manifold didn't fit the milled heads, so Hafliger had to machine 0.060 inch from Edelbrock's Performer RPM intake manifold to get it to seal to the intake ports properly. That's Brian's dad, Fred, on the right. He's the other half of IMM Engines. Yup, it's just a two-man shop.The intake manifold didn't fit the milled heads, so Hafliger had to machine 0.060 inch fro Finally, Hafliger had to install shorter-than-stock pushrods. These are Manley's 8.50-inch, 5/16-inch wall-thickness pushrods.Finally, Hafliger had to install shorter-than-stock pushrods. These are Manley's 8.50-inch To complement its Performer RPM intake manifold, Edelbrock provided a pair of its Signature Series valve covers. They fit perfectly and kept oil leaks at bay. We topped the intake with an out-of-the-box 0779 Holley 750 Double Pumper. That's MSD's new Pro-Billet Ready-to-Run distributor powered by MSD's Pro Power HVC coil. The wires are MSD's Street Fire series, and we used Autolite 86 plugs, stock replacements for a 383 Roadrunner.To complement its Performer RPM intake manifold, Edelbrock provided a pair of its Signatur Because of our recent troubles breaking in flat-tappet cams, we filled the crankcase with Comp's 10W-30 Engine Break-In oil. It's brewed with extra zinc, phosphorous, and molybdenum. While we don't recommend doing shots with the stuff, the cam and lifters broke in perfectly.Because of our recent troubles breaking in flat-tappet cams, we filled the crankcase with With air/fuel ratios mostly in the mid-13 range, the engine also wanted more fuel. Hafliger went up four jet sizes, front and rear, resulting in a 12.5:1 ratio throughout the powerband.With air/fuel ratios mostly in the mid-13 range, the engine also wanted more fuel. Haflige Hafliger initially set the advance to a conservative 32 degrees. After a few short pulls, he decided the engine wanted more and cranked in 34 degrees.Hafliger initially set the advance to a conservative 32 degrees. After a few short pulls, SOURCES Tube Technologies, Inc. 1555 Consumer Circle Corona CA 92880 951-371-4878 http://www.ttiexhaust.com/ MSD 915-857-3344 www.MSDIgnition.com Automotive Racing Products 1863 Eastman Ave Ventura CA 93003 800-826-3045 www.arp-bolts.com Comp Cams 3406 Democrat Road Memphis TN 38118 800-999-0853 www.compcams.com Summit Racing Equipment PO Box 909 Akron OH 44398 800-230-3030 330-630-0240 www.summitracing.com Holley Performance Products 1801 Russellville Rd P.O. Box 10360 Bowling Green KY 42102 270-782-2900 www.holley.com IMM Engines Indio CA 760-347-5493 www.immengines.com 440Source Lancaster CA 661-951-3700 www.440Source.com eBay Motors www.ebaymotors.com Edelbrock 2700 California St. Torrance CA 90503 310-781-2222 www.edelbrock.com By John McGann Enjoyed this Post? 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