|
|
434ci Small-Block Engine Build - The Bigger MousePacking a Punch With a 434ci Small-Block Stroker From the March, 2012 issue of Chevy High Performance By Henry De Los Santos Photography by Damon Rivetti, Henry De Los Santos
|
|
We’re still enamored with conventional small-blocks, and this month we put together the ultimate thumper for any street machine. That means we didn’t go overboard with a radical camshaft or shoot for the sky with monster compression; instead, we went big with the cubic inches, installed a hydraulic roller cam, and topped it off with a 4150-style carburetor. To get this build going, we went to our favorite machine shop, A.R.E. Performance & Machine in Simi Valley, California, where we assembled our 434ci small-block combo. We started by ordering a Dart SHP block outfitted with a stout rotating assembly, including a 4-inch stroker crankshaft, 6-inch rods, and forged pistons. For induction duties, we relied on a pair of healthy lungs from Dart’s line of Pro1-series CNC-ported 227 cylinder heads and matched it up with Dart’s single-plane manifold. We ordered our fully assembled... We ordered our fully assembled 434ci short-block from Dart Machinery. Think of it as a made-to-order package, allowing you to outfit it with your choice of components to best suit your needs and application. The 227 heads are impressive to say the least, flowing 309 cfm on the intake and 226 cfm on the exhaust at 0.700-inch lift; granted, we used a rather small hydraulic roller and only took advantage of the flow in the mid 0.550-inch range, but this would allow us to grow into this combination in the months to come. You didn’t really think we would stop, here did you? For this build, we wanted to focus on a truly streetable combination that would make for a good cruiser, both on the open highway and for the occasional romps, be it on the tarmac or on an autocross course. Why the 434? That’s easy, we wanted big-block–like torque that could move everything from a portly land yacht to a svelte lightweight that could take advantage of the horsepower-to-weight ratio. Given the post Westech Performance Group dyno numbers shown on page 24, we think you’ll agree, this combination produced a great, usable powerband and could supply a lot of fun in any given chassis. Where do we go from here? Honestly, there’s a nitrous system we’ve been eyeing recently, and a number of dyno tests we’ve been itching to do. Is there something in particular you would like to see? If so, email us at chevyhi@sorc.com or post it up on our Facebook page at facebook.com/chevyhiperformance and let us know!  The block itself is Dart’s...  The block itself is Dart’s SHP block that’s been punched out to a 4.155-inch bore with four-bolt ductile iron main caps on the center three and two-bolt caps on the end. The bottom end features all forged internals, including a 4-inch 4340 crankshaft, 6-inch 4340 rods with ARP 2000 rod bolts, and 10:1 compression pistons. Pretty stout, right? And it’s more than capable of handling big power.  Taking a peek inside, the...  Taking a peek inside, the cam bearings were already installed and waiting for our new bumpstick.  For heavy breathing, Dart’s...  For heavy breathing, Dart’s Pro 1 CNC-ported 227 cylinder heads feature a 66cc combustion chamber and 2.08/1.600-inch intake/exhaust valves, and are made of quality 355-T61 aluminum alloy.  The intake side uses a Fel-Pro...  The intake side uses a Fel-Pro 1206 gasket, measuring in at 2.200 by 1.310 inches, and can flow up to 309 cfm at 0.700-inch lift. The exhaust port features an 85cc port, sizes in at 1.410 by 1.585 inches, uses a Fel-Pro 1405 gasket, and flows up to 226 cfm at 0.700-inch lift.  To complement the Pro 1 227s,...  To complement the Pro 1 227s, we used a Dart single-plane manifold. Given the cubic inches and long stroke, we weren’t worried about torque and wanted to get the maximum horsepower available with our small-block combination.  For the current test, we left...  For the current test, we left everything as is in its out-of-the-box configuration, to produce real-world results. For our next session, you can bet we’ll port-match the intake to the cylinder heads and see if we can’t extrapolate a bit more.  We went with COMP Cams’ 1.6-ratio...  We went with COMP Cams’ 1.6-ratio Ultra Pro Magnum rocker arms; these gems are built out of 8650 chrome-moly steel and designed with a weblike structure to add strength where it’s needed and reduced mass in low-stress areas. All this helps provide maximum lift and the ultimate valvetrain control in the upper rpm range.  At the heart of the 434ci...  At the heart of the 434ci is a COMP Extreme Energy hydraulic roller retrofit camshaft with 236/242 degrees duration and 0.520/0.540-inch lift at 0.050 on a 110 LSA.  Rounding out the COMP valvetrain,...  Rounding out the COMP valvetrain, we used a set of 0.842-inch diameter High Energy hydraulic lifters; these are designed for all of COMP’s latest hydraulic roller cams or as a performance replacement for factory hydraulic roller lifters.
|
|
|