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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
  • Jenkins Smeding 406Ci Small Block Chevy Crate Engine
    Once the bottom end is done, which takes up most of the build time, things speed up.
  • Jenkins Smeding 406Ci Small Block Chevy Crate Engine
    The oil pump used in the 406 is a standard volume Melling oil pump.
  • Jenkins Smeding 406Ci Small Block Chevy Crate Engine
    The two-piece Comp Cams timing cover that is being installed in this photo is for the test build engine.
    Jenkins Smeding 406Ci Small Block Chevy Crate Engine
    The two-piece Comp Cams timing cover that is being installed in this photo is for the test
  • Jenkins Smeding 406Ci Small Block Chevy Crate Engine
    The Canton oil pan has a seven-quart capacity.
  • Jenkins Smeding 406Ci Small Block Chevy Crate Engine
    Jenkins and Smeding talk shop as Ben works on a set of cylinder heads.
  • Jenkins Smeding 406Ci Small Block Chevy Crate Engine
    The top half of the engine consists of AFR 195 cylinder heads with 65cc combustion chambers.
    Jenkins Smeding 406Ci Small Block Chevy Crate Engine
    The top half of the engine consists of AFR 195 cylinder heads with 65cc combustion chamber
  • Jenkins Smeding 406Ci Small Block Chevy Crate Engine
    The lightweight intake valves measure 2.050-inch and the exhausts are 1.600 with hardened ductile iron interlocking valve seats. The intake used is an Edelbrock Super Victor topped with a Quick Fuel 750 cfm double pumper.
    Jenkins Smeding 406Ci Small Block Chevy Crate Engine
    The lightweight intake valves measure 2.050-inch and the exhausts are 1.600 with hardened
  • Jenkins Smeding 406Ci Small Block Chevy Crate Engine
    Once the engine was on the dyno and the rings were seated, a few different tests and parts swaps were conducted.
    Jenkins Smeding 406Ci Small Block Chevy Crate Engine
    Once the engine was on the dyno and the rings were seated, a few different tests and parts
  • Jenkins Smeding 406Ci Small Block Chevy Crate Engine
    After we left Smeding Performance, they tried one last dyno run this time with a highly-tuned 850 cfm Quick Fuel carb with the Professional Products Hurricane intake. Ben informed us that the Quick Fuel carb was within 4 horsepower of the Mighty Demon. As for the final production version of this engine that hits the streets, well, that is up to Jenkins and Smeding.
    Jenkins Smeding 406Ci Small Block Chevy Crate Engine
    After we left Smeding Performance, they tried one last dyno run this time with a highly-tu
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
COMP Cams Smeding Performance
Dept. MMFF
3340 Sunrise Blvd.
Rancho Cordova
CA  95742
Barry Grant Demon Carburetion Edelbrock
Dept. 5.0
2700 California St.
Torrance
CA  90503
310-781-2222
www.edelbrock.com
Dart
2-48/-362-1188
www.dartheads.com
Air Flow Research
10490 Ilex Avenue, Dept. MMFF
Pacoima
CA  91331
Quick Fuel Technology
Bowling Green
KY
2-70/-793-0900
quickfueltechnology.com
By Mike Harrington
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