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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
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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.  To keep the cylinder heads...  To keep the cylinder heads in place, we went with a complete set of ARP head studs because we’re planning to add an extra kick to this build. Another option is to use ARP head bolts (PN 134-3601).  To seal the pressure chamber,...  To seal the pressure chamber, we used Fel-Pro PermaTorque MLS head gaskets with a 0.041-inch thickness.  With the MLS gasket and ARP...  With the MLS gasket and ARP head studs in place, lead man Rocco Acerrio of A.R.E Performance & Machine laid down the Dart 227 cylinder head into position.  Next, the COMP camshaft was...  Next, the COMP camshaft was coated liberally with assembly lube and slid into place. While the cam is spec’d with 0.520/0.540-inch lift with 1.5-ratio rocker arms, we stepped up to a 1.6 ratio, giving us a bit more at 0.555/0.576-inch lift.  Checking for pushrod length,...  Checking for pushrod length, it measured in at 7.500 inches for both the intake and exhaust sides.  With the 227 cylinder heads...  With the 227 cylinder heads in place, each bolt was then torqued to 80 ft-lb.
| Flow Data |
|
Intake |
Exhaust |
| 0.200 |
158 |
117 |
| 0.300 |
209 |
149 |
| 0.400 |
257 |
182 |
| 0.500 |
293 |
211 |
| 0.600 |
302 |
220 |
| 0.700 |
309 |
226 |
| *cfm at 28 inches H20 |
 When it came to the timing...  When it came to the timing chain, we used COMP’s Keyway adjustable billet timing set. This double-roller assembly has a nine-keyway crank sprocket that offers 2-degree incremental adjustability with a maximum 8-degree advance/retard.  We went with COMP’s two-piece...  We went with COMP’s two-piece billet aluminum timing cover for a few reasons. Obviously, we like the way it looks, but more importantly, it’s very functional. The cover is rigid and will hold the camshaft in place without any flexing issues. Also, endplay adjustments are a breeze with the access hole for a dial indicator. Lastly, the two-piece configuration allows for easy camshaft swaps without having to mess with the oil pan seal.
| Dart Pro 1 CNC 227 Specs |
| Intake port |
227cc |
| Chamber volume |
66cc |
| Intake/exhaust valves |
2.08/1.60 |
 Topping off the 434 ci is...  Topping off the 434 ci is Dart’s single-plane manifold. Once sealed with the Fel-Pro 1206 intake gaskets, the ARP bolts were then torqued to 35 ft-lb.  On the dyno, we relied on...  On the dyno, we relied on a Moroso DuraFire HEI distributor to light the fire. The all-in-one system incorporates a Moroso ProCoil and allows you to change the advance curve for your combination.  If you didn’t already know,...  If you didn’t already know, COMP offers a line of synthetic oils, dubbed Muscle Car & Street Rod Engine Oil; we used seven quarts of 10W-30.  Fueling the entire package...  Fueling the entire package is Holley’s latest 750 Ultra HP. As we expected, out of the box the carb was near perfect. Our first steady state pull at 4,500 rpm showed air/fuel readings around 12.8. We eventually swapped out the jets to 73/74 (primary/secondary) for peak performance numbers.
Cam Specs |
| Manufacturer |
COMP Cams |
| PN |
12-433-8 |
| Grind number |
XR288HR |
| Type |
hydraulic roller |
| Valve lift |
0.520/0.0540-inch, intake/exhaust |
| Duration at 0.050 |
236/242 degrees, intake/exhaust |
| Lobe separation angle |
110 degrees |
Dyno Details |
| Headers |
13/4-inch long-tube headers with 18-inch extensions and mufflers |
| Advance |
39 degrees |
| Fuel |
91-octane |
| Carb |
Holley 750 Ultra HP |
| Jets |
73/74 |
| Max Torque |
552 at 4,500 |
| Max Power |
542 at 5,700 |
| Avg. Torque |
461 |
| Avg. Power |
527 |
| 434 Buildsheet |
| Displacement |
434 |
| Bore x stroke |
4.155 by 4.000 inches |
| Compression |
10.3:1 |
| Rod center-to-center |
6.00 inches |
| Piston deck height |
0.000 |
| Chamber volume |
66cc |
| Rod bearing clearance |
0.0025 |
| Crank endplay |
0.007 |
| Main bearing cap torque |
1-5 7/16 bolts 65 ft-lb (moly-lube) |
| 2, 3 & 4 3/8 bolts 35 ft-lb (moly-lube) |
| Rod bolt torque |
70 ft-lb (moly-lube) |
| Head bolt torque |
80 ft-lb (moly-lube) |
| By The Numbers |
| RPM |
TQ |
HP |
| 3,200 |
499 |
304 |
| 3,300 |
500 |
314 |
| 3,400 |
505 |
327 |
| 3,500 |
515 |
343 |
| 3,600 |
526 |
360 |
| 3,700 |
533 |
376 |
| 3,800 |
540 |
391 |
| 3,900 |
546 |
405 |
| 4,000 |
549 |
418 |
| 4,100 |
550 |
430 |
| 4,200 |
551 |
441 |
| 4,300 |
551 |
451 |
| 4,400 |
551 |
462 |
| 4,500 |
552 |
473 |
| 4,600 |
552 |
484 |
| 4,700 |
551 |
493 |
| 4,800 |
549 |
502 |
| 4,900 |
546 |
510 |
| 5,000 |
542 |
516 |
| 5,100 |
538 |
522 |
| 5,200 |
533 |
528 |
| 5,300 |
528 |
533 |
| 5,400 |
522 |
537 |
| 5,500 |
515 |
539 |
| 5,600 |
507 |
540 |
| 5,700 |
499 |
542 |
| 5,800 |
491 |
542 |
| 5,900 |
481 |
541 |
| 6,000 |
472 |
540 |
 Moroso’s Ultra 40 wire set...  Moroso’s Ultra 40 wire set carries the spark into the chambers.  Pressurizing the oiling system...  Pressurizing the oiling system is Moroso’s oil pump and pickup package. The pickup itself is factory welded to the pump, and the mesh screen traps any unwarranted debris.  Because it’s designed for...  Because it’s designed for the occasional dragstrip use, we chose Moroso’s 7-quart oil pan. This pan is made to fit on ’85-and-earlier blocks or any with a two-piece rear main seal. (Note: This pan has no provision for the use of a factory dipstick.) CHP
| Parts List | |
| MFG |
PN |
Item |
| ARP |
234-4301 |
head studs |
| 400-7614 |
valve cover studs |
| 400-1212 |
header bolts |
| 435-1902 |
oil pan studs |
| 230-7004 |
oil pump stud |
| 334-1401 |
timing cover |
| 430-3201 |
water pump |
| 434-2001 |
intake |
| 300-2404 |
carb studs |
| 430-1702 |
distributor stud |
| 134-2501 |
damper bolt |
| 300-1001 |
cam bolt |
-
| 134-7901 |
oil pump drive |
| 200-2902 |
flexplate |
| COMP Cams |
12-433-8 |
Extreme Energy retrofit camshaft |
| 7100 |
Keyway adjustable billet timing set |
| 210 |
two-piece billet aluminum timing cover |
| 1605-16 |
1.6 Ratio Ultra Pro Magnum rockers |
| 853-16 |
High Energy hydraulic roller lifters |
| 7957-16 |
7.500-inch, 5/16 Hi-Tech pushrods |
| 4506-16 |
7/16 Hi-Tech rocker arm studs |
| Dart |
Call |
434 short-block |
| 11970040P |
Pro1 CNC 227 aluminum heads |
| 68000015 |
valve covers |
| 42412000 |
single-plane manifold |
| Federal-Mogul |
1144 (2) |
head gaskets |
| 1206 |
intake gaskets |
| 1405 |
exhaust gaskets |
| 1880 |
oil pan gasket |
| 2701 |
R.A.C.E |
| 1928 |
valve cover gaskets |
| Holley |
0-80803BK |
750 Ultra HP |
| Moroso |
20196 |
oil pan |
| 22134 |
oil pump and pickup |
| 25971 |
dipstick |
| 72230 |
DuraFire distributor |
| 73607 |
Ultra 40 Race ignition wire set |
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