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Small-Block Chevy Crate Engine - Own Another Piece Of The Grump

This Month We Take A Look At The Jenkins/Smeding 406 Small-Block

By Mike Harrington, Photography by Mike Harrington

Sometimes lightning does strike twice. The first bolt that struck was the 572 cubic-inch big-block Jenkins/Smeding Performance engine that we ran a story on in our December '08 issue. Ready for a second helping of horsepower, legendary racer Bill "Grumpy" Jenkins and Ben Smeding have teamed up once again to build a street-friendly 406 small-block.

As was the case with the 748-horse 572 build, the signature 406 will be produced in a limited quantity. Each of these engines is fully balanced, blueprinted, and dyno tested before it leaves the shop. And those results come only after a series of dyno tests and parts swaps. Only when both men are satisfied will the 406 be built and produced.

Once again, we spent a couple of days up at Smeding Performance documenting the build and test runs of this big small-block.

Dyno Test 1
Maximum HP Maximum Torque
526@5,800 RPM 519@4,800 RPM

Parts list: Edelbrock Super Victor single plane intake, Smeding rocker arms, AFR 195 cylinder heads Quick Fuel Technologies 750 cfm carb and MSD Pro Billet distributor. At lower range between 2500 and 3000 rpm, the engine torque starts between 431 and 458 ft-lbs and quickly accelerates from there until it hits its peak.

Dyno Test 2
Maximum HP Maximum Torque
554@6,100 RPM 535@5,000 RPM

Parts list: This test consisted of the same exact parts as in the first dyno test with the exception of the carburetor. A highly-tuned Barry Grant 830 cfm Mighty Demon annular carb was swapped in place of the QFT 750. The torque gain was 28 ft-lbs and the horsepower gain was 16.

Dyno Test 3
Maximum HP Maximum Torque
549@6,000 RPM

532@5,000 RPM

For this test, the Demon carb was kept and the Edelbrock Super Victor was swapped in exchange for a Professional Products Hurricane intake. The results were nearly the same, minus the 5 hp loss and 3 ft-lbs of torque lost at peak.

SOURCES
Air Flow Research
10490 Ilex Avenue, Dept. MMFF
Pacoima
CA  91331
Edelbrock
Dept. 5.0
2700 California St.
Torrance
CA  90503
310-781-2222
www.edelbrock.com
Barry Grant Demon Carburetion Quick Fuel Technology
Bowling Green
KY
2-70/-793-0900
quickfueltechnology.com
COMP Cams Smeding Performance
Dept. MMFF
3340 Sunrise Blvd.
Rancho Cordova
CA  95742
Dart
2-48/-362-1188
www.dartheads.com
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By Mike Harrington
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