Chrysler 400 - 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 Chrysler 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 Chrysler 400 engine can be built at home. There were no exotic Hemi 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 Chrysler 400, and make some Hemi power.
Chrysler 400 Hemi 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.
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
