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Small Block Chevy Stroker - A Stroke Of Genius Part II

Hye Tech Performance Seals Up Its 391 Stroker Small-Block

Mike Petralia Jul 1, 2001
Sucp_0107_01_z Small_block_chevy_stroker Intake_manifold 2/16

It's all about breathing. Since we love small-blocks, but we love big cubic inches even more, stroker small-blocks are tops in our book. Big cubic inch small-blocks need lots of breathing room, and this month we're going to show you how to build the top end of an outstanding street stroker. Last month we told you about our feelings for the oft-built 383 small-block stroker. While the 383 is a fun and affordable motor to build, it's also very common and has consequently become somewhat of a bore to read about. For a new angle on strokers we hooked up with Sod Bogosian, owner of Hye Tech Performance in El Monte, California, where he showed us how to stroke a small-block from a different point of view.

Unique Stroker Recap
Hye Tech Performance has taken the ordinary 383-stroker concept to the next level. By offset grinding the rod journals of a new C.A.T. Power Engine Parts 3.75-inch stroke, 4340-forged crankshaft to the smaller 2.00-inch diameter of the old 327 rod journal, Bogosian has created a reliable 3.832-inch stroke small-block crank. After boring a 350 block 0.030-inch over-size, Bogosian can assemble an affordable 391-cid street stroker using his custom crank. To further enhance power and strength of his long-arm Mouse, Bogosian installs C.A.T. 5.7-inch, 4340 H-beam connecting rods and 10.25:1 compression forged JE flat-top pistons. This bottom-end combination makes for a fast-accelerating and good-torque-generating small-block that'll last just about forever on 92-octane pump gas.

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Last month Roland Marquez from Hye Tech Performance assembled the rotating assembly of this 391-cid stroker small-block. The first parts bolted on this month were a Milodon Hi-Volume oil pump with a reinforced pickup and a pan baffle wedged under the pump to keep oil from climbing the back of the block under hard acceleration.

Stroker Top End
Any stroker small-block worth its displacement has to breathe in order to make power. The longer stroke in these engines means that they can use a camshaft that's a little bigger than you'd normally see inside a 350-cid small-block. To give the 391-cid Mouse some breathing room Bogosian chose Holley's dyno-matched Street Avenger system, including a new Street Avenger 770-cfm vacuum secondary carburetor with Street Avenger aluminum cylinder heads and intake manifold. And since Lunati is also a Holley Performance Company, both companies have worked closely developing a dyno-matched hydraulic cam/lifter package for the Street Avenger system, and Bogosian ordered the complete set, along with Lunati 1.6:1 aluminum roller rockers and a double-roller timing chain from Jeg's High Performance.

By running a proven package, Bogosian knew he could side step testing various components on his own time in order to achieve the best power levels. He also explained that this engine's owner was not looking for maximum peak horsepower, rather he wanted a strong small-block with a very wide and smooth power band for both cruising and bangin' gears. To that effect, Bogosian chose a camshaft that may seem a bit big for the average street small-block but will compliment all that this stroker's almost 400 inches has to offer.

Although they can add power to the engine, windage screens like this one usually require modification/adaptation to work in street engines. Photo A shows the bolt hole that was opened up to clear the dipstick. Photo B shows where the tray was clearanced to fit around the dipstick tube. Note also that the main cap stud directly in line with the dipstick was replaced with a bolt for clearance.

Marquez checks the Fel-Pro one-piece oil pan gasket for clearance around the windage tray. The gasket fits well, but it must be laid in place prior to installing the windage screen so it will fit over the lower dipstick tube. Note the ratchet on the end of the crank that Marquez uses to rotate the crank 360 degrees to make sure everything completely clears the windage screen.

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This Milodon oil pan is clearanced for longer stroke engines, and Marquez lowers the pan on for a fit check, finding that there were no interference problems.

Breathing Room
If your engine doesn't get enough air into its cylinders, then it won't be able to produce power it can be proud of. Besides the camshaft, the cylinder heads affect breathing more than any other component. To get the best breathing possible without sacrificing streetable low-end power, Holley's Street Avenger cylinder heads feature an efficient 184cc intake runner volume. With its high-tech 68cc combustion chamber, and 2.02/1.60-inch stainless valves, the Avenger heads flow 223 cfm on the intake side and 173 cfm on the exhaust, both at 0.500-lift.

That works out to an impressive 78 percent intake to exhaust flow ratio, and since we know that max cfm through the cylinder heads does not always equate to max power at the crank, we agreed with Bogosian that these cylinder heads should produce a strong and wide power band that will probably top out around 6,200 rpm on this engine. Capped off with Holley's dual-plane Street Avenger intake manifold and the vacuum secondary carb, this engine should pull some great bottom-end grunt!

Light The Fire
A hot street engine can't do diddly without a hot spark, so Bogosian again choose the dyno-matched route and will install Holley's complete Annihilator ignition system, including a billet distributor, wires, a coil, and a digital spark box. Capable of supplying enough voltage to power a diesel/electric submarine, the Annihilator ignition should have no trouble lighting this big Mouse's fire! Also to be added before the dyno test session, will be a Holley mechanical fuel pump, Lunati pushrods, and a Weiand mechanical water pump with March Performance serpentine pulleys. Check back with us next month as we detail the dyno test session and find out if the stroker from a different point of view can muster the power to run with the big dogs.


March Performance
Naples, FL 34110
Manley Performance Products
Lakewood, NJ 08701
JE Pistons
Huntington Beach, CA 92649
Holley Performance Products
Bowling Green, KY 42101
Lunati LLC
Olive Branch, MS
Jeg's High Performance
Delaware, OH 43015
(800) 345-4545
C.A.T. Power engine parts
Baldwin Park, CA 91706



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