The Chevy 409 has earned a rightful place in high-performance history thanks to its early success in Super Stock drag racing--and a certain pop song by the Beach Boys. But with a relatively brief production run that lasted from 1961 through 1965 in cars and 1962 through 1966 in trucks, perhaps only 100,000 409s were produced. Finding a good one today is next to impossible, and if you do, you'll need to wrestle it away from the restoration crowd.
Few enthusiasts realize there's a budget-friendly alternative to a scarce 409. We're talking about the comparatively unloved 348. Introduced in 1958 as the first member of Chevy's big-block engine family, hundreds of thousands were installed in passenger cars between 1958 and 1961, plus a bunch more in heavy-duty 1-ton Chevy trucks right up through 1966. Most experts agree that 348 production outpaced 409 production 5-to-1, so there are still plenty to choose from. We see 'em at swap meets all the time.
No, the 348 never inspired a hit pop song, but thanks to renewed interest from the aftermarket, you can transform a 348 into a 434-cube monster with enough power to rival any similarly built small- or big-block. The key ingredients are Edelbrock's new Performer RPM 409 aluminum heads, an Eagle stroker crank and H-beam rods, Ross pistons, an Isky solid roller cam, and a new single-plane four-barrel intake manifold from Lamar Walden.
Roll it all together with quality machine work, and you're looking at well over 500 hp at 6,200 rpm and 500 lb-ft at 5,500 rpm. The upshot is that we have a potent new engine family to play with, and can you imagine the shocked look on people's faces when you pop the hood on your Camaro, Chevelle, or Nova and they see one of these?
Let's watch as Joe Jill and the crew at Superior Automotive prepare and assemble the stroked short-block. Next month we'll complete the buildup and run it on the dyno.
Quick Notes
What We Did
Transform a forgotten 348ci into a stroker 434ci
Bottom Line
Its a potent package!
Cost (Approx)
$8,500
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Before delving into the assembly, a quick look at the W's unique chamberless cylinder head
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Because of the tilted deck surfaces, traditional deck height measurement techniques are no
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Our 348ci to 434ci recipe starts by boring the stock 4.125 bores 0.030 over to 4.155 inche
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Billet steel main caps from CRV 409 Parts are added to the center three positions and boos
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The key ingredient in the stroker assembly is this forged 4340 steel Eagle crank. Its 4-in
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The extra 3/4 inch of stroke creates block contact. Jill says he also encounters this when
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Several shallow notches are all it takes to restore free movement. It's imperative to mock
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Edelbrock warns that its Performer RPM 409 heads must be limited to 0.550 maximum valve li
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Here's a view of the trouble spots from inside the crankcase. While 409 blocks feature lar
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While the 2.190 intake valves are good to go on the 348, the W's staggered valves rely on
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With plenty of moly grease to protect the valve guides, the heads are mounted to the block
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The pen points to the reworked valve pocket. All 348 blocks feature these machined pockets
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High-pressure valve springs (over 350 pounds) tend to smear rebuilder-grade cam bearings.
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The oil feed holes in the No. 5 cam bearing work in conjunction with an oil channel on the
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The Eagle stroker crank rides on semigrooved Federal-Mogul main bearings (PN 4036M). The m
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Compared to the stock forged rods (right) the 6.135-inch Eagle H-beams (PN CRS61353D) look
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The forged 11.7:1 Ross pistons (PN JC120905) weigh 782.2 grams, 173.2 grams less than the
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The unique angle of the 348 deck requires a band-type ring compressor. It's thin enough to
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With the piston at TDC, the sloped dome creates a 59.76cc wedge-shaped combustion chamber.
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The Eagle rod caps torque to 63 ft-lb and use Clevite 77 rod bearings (PN CB-743HN). Oil c
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The W-motor accepts small-block oil pumps, so a Melling 302 Z/28 high-volume unit gets the
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Stock 348/409 crank snouts accept small-block dampers, but differences in keyway placement