We initially tossed the idea of comparing a stock LS1 with a conventional small-block 350, but after questioning the angle we later realized, what's the fun in that? And dare we say, it's already been done by others who'll be the first to admit that they did a fair job of updating you with the crucial differences-but certainly did little to stimulate the gearhead factor. To kick it up a notch, and satiate our hunger for power, we set the stage to bump up the cubic inches of a later-model LS2 into a big-inch 402 and pin it against a "warmed over" 406ci small-block.

Our requirements for this challenge: All components had to be readily available, over-the-counter production pieces; nothing over 11:1 compression; we had to use a hydraulic-roller camshaft; and we had to keep the components as close as possible, meaning we had to use the same manufacturer for our cylinder heads, camshafts, and manifolds, and most importantly, both bullets had to share the same carburetor.

Doesn't seem like that big a deal, right? Wrong. You need to take a closer look at the flow capacity of an LS cylinder head. Given the nature of its 15-degee valve angle over the conventional 23-degree cylinder head, we're talking race technology that's trickled down to the consumer level. By altering the angle of the valve, you create a much more direct path, which allows a greater volume of air to traverse into the combustion chamber at a faster rate. The result is radical flow numbers that help to create big horsepower. As you can imagine, the obvious advantage already went to the LS before we even began building the engines.

The real question becomes, was either engine significantly cheaper or did one walk away as the clear winner? Follow along, and you be the judge. Don't forget to write in to us at chevyhi@ primedia.com and let us know what you think of the results.

Turn Key 402ci
For this build I enlisted the help of Turn Key Engine Supply in Oceanside, California, and engine builder Chris Pollock, whom we have to give major props to. Considering our dyno session was scheduled for the following day, these guys had the entire bullet built from scratch to finish in a matter of hours. Then again, when your business is in the habit of cranking out 40-plus turnkey engines a month, it's just another day in the office.

Now I'm not going to give you a history lesson, but I do want to point out that the LS1 first debuted back in '97, and while it may seem hard to swallow, the newfangled LS variants are already going on their 10th year! Point being, it's not that new, folks. If you aren't familiar with the 6.0L LS2, don't sweat it. It's still in the same platform as the Gen III LS1/LS2 and the 5.3L and LQ9 6.0L truck engines. Matter of fact, all the parts available for this engine family are interchangeable, and it closely resembles the LQ9 truck motor, with the exception of its aluminum construction over the cast iron. Other differences include the relocation of the cam sensor from the rear of the engine to the front and the loss of dual knock sensors in the valley pan, which are now located on the side of the block.

Getting on to the mule, the initial plan was to build on a cast-iron LQ9; however, after pricing out bare blocks, we learned that the aluminum LS2 was only $300 more. Given the similar construction, it only seemed fitting to try something new. Besides, a motor that weighs significantly less only adds to the cool yet functional factor when dropped in between the fenderwells of any street machine. I'll let the following pages reveal the sordid details, including the price breakdown, the components used, and the dyno results.

If you're curious as to my interpretation of this month's test, I will say that the overall results left a permanent impression. Considering the LS2 churned out well over 560 hp and 520 lb-ft with excellent idle quality at 13 inches of vacuum, it's a true driver. And yes, that's on 91-octane. As an added bonus, we swapped the camshaft and went up another 8 degrees of duration, improving on our numbers with over 580 hp and 530 lb-ft, all the while maintaining 10 inches of vacuum at idle. As for the older Mouse, it was impressive, to say the least, but it's far more aggressive and lends itself as more of a weekend brawler when compared with this LS2. That said, dollar for dollar, at least in this comparison, the 402 LS2 proved that it can not only produce serious power, but with a relatively mild build it's perfectly suitable for the street. I'd like to see what this combination could produce with a stout solid-roller, but that's a story for another month.

Q&A With Kolby Enger From Turn Key SupplyCHP: Walking through your facility was almost a mirrorlike experience to walking through a GM warehouse. What are the bulk of the builds you do on a regular monthly basis?

Kolby Enger: Our primary sellers are the 450- to 500hp versions of the LS1s, and more recently we're starting to see more 500-plus-horsepower LS2s with forced induction going out the door.

CHP: Are you noticing any kind of trend in sales with the LS-series engines? KE: A lot of guys out there are building musclecars and outfitting them with modern-day components, including the suspension and drivetrain. Lately, we've been selling an incredible number of LS engines with retro kits that'll allow for a perfect fit underneath the stock hood while utilizing the existing motor mounts.

CHP: Is there a particular combination that outsells the rest?KE: Our engine-swap kits for '67-69 Camaros and '55-57 Chevys seem to be really hot right now.

CHP: What is it about the LS engines that you prefer over the older conventional small-blocks?KE: There are a few things, such as the aluminum construction and the bottom-end torque, and while the carburetor versions work well, we're partial to the electronic fuel-Injection setup. The EFI system we offer is fully programmable and capable of tuning any combination a customer can dream of. If a customer wants an out-the-door twin turbo system that can produce over 1,000 hp with a tune, we can do that too.

Camshaft Specifications

CAM I
MANUFACTURER Comp Cams
PART NUMBER 54-446-11
TYPE Hydraulic roller
VALVE LIFT AT 0.050 0.595/0.598 inch, intake/exhaust (factory rockers)
DURATION AT 0.050 232 /234 degrees, intake/exhaust
LOBE SEPARATION 112 degrees
CAM II
MANUFACTURER Comp Cams
PART NUMBER 54-448-11
TYPE Hydraulic roller
VALVE LIFT AT 0.050 0.605/0.609 inch, intake/exhaust (factory rockers)
DURATION AT 0.050 238/240 degrees, intake/exhaust
LOBE SEPARATION 112 degrees

DYNO DETAILS
Headers 13¼4 Hooker long-tubes
Fuel 91-octane unleaded  
CAM I   CAM II   Cam II with 1-inch HVH Spacer
Advance 31 degrees Advance 33 degrees Advance 33 degrees
Max torque @ rpm 523.4 lb-ft @ 5,100 Max torque @ rpm 527.9 lb-ft @ 5,100 Max torque @ rpm 529.6 lb-ft @ 5,200
Max power @ rpm 562.8 hp @ 6,400 Max power @ rpm 577.9 hp @ 6,500 Max power @ rpm 583.2 hp @ 6,600
Average torque 483.7 lb-ft Average torque 484.5 lb-ft Average torque 484.5 lb-ft
Average power 418.9 hp Average power 437.5 hp Average power 438.0 hp
RPM LB-FT HP RPM LB-FT HP RPM LB-FT HP
2,600 426.2 211.0 2,600 425.5 210.6 2,600 411.6 203.8
2,700 422.1 217.0 2,700 420.9 216.4 2,700 408.1 209.8
2,800 421.0 224.5 2,800 420.2 224.0 2,800 409.2 218.1
2,900 425.1 234.7 2,900 424.5 234.4 2,900 415.4 229.4
3,000 433.4 247.5 3,000 432.9 247.3 3,000 426.4 243.5
3,100 440.5 260.0 3,100 443.4 261.7 3,100 437.8 258.4
3,200 447.5 272.6 3,200 452.0 275.4 3,200 448.1 273.0
3,300 455.2 286.0 3,300 457.6 287.5 3,300 455.4 286.1
3,400 460.4 298.0 3,400 460.7 298.3 3,400 459.5 297.5
3,500 462.7 308.4 3,500 463.2 308.7 3,500 461.8 307.7
3,600 464.6 318.4 3,600 465.9 319.3 3,600 464.6 318.4
3,700 468.2 329.9 3,700 469.2 330.5 3,700 468.9 330.3
3,800 473.9 342.9 3,800 474.1 343.1 3,800 475.0 343.7
3,900 481.6 357.6 3,900 480.9 357.1 3,900 481.9 357.8
4,000 488.9 372.3 4,000 487.1 371.0 4,000 488.9 372.3
4,100 495.1 386.5 4,100 493.0 384.9 4,100 495.8 387.0
4,200 499.3 399.3 4,200 498.6 398.7 4,200 501.7 401.2
4,300 502.2 411.2 4,300 503.3 412.1 4,300 506.9 415.0
4,400 504.7 422.9 4,400 508.4 425.9 4,400 509.8 427.1
4,500 508.0 435.2 4,500 513.0 439.5 4,500 512.7 439.3
4,600 511.2 447.8 4,600 516.5 452.4 4,600 516.2 452.1
4,700 514.6 460.5 4,700 520.7 466.0 4,700 520.7 465.9
4,800 518.3 473.7 4,800 524.5 479.3 4,800 524.1 479.0
4,900 521.2 486.2 4,900 526.4 491.1 4,900 526.5 491.3
5,000 522.9 497.8 5,000 527.5 502.2 5,000 528.3 502.9
5,100 523.4 508.2 5,100 527.9 512.6 5,100 529.5 514.2
5,200 522.1 516.9 5,200 527.8 522.6 5,200 529.6 524.4
5,300 520.1 524.8 5,300 527.2 532.0 5,300 528.5 533.3
5,400 517.9 532.5 5,400 525.8 540.6 5,400 526.6 541.5
5,500 515.5 539.9 5,500 523.5 548.2 5,500 524.0 548.8
5,600 512.0 545.9 5,600 520.5 555.0 5,600 520.8 555.3
5,700 507.7 551.0 5,700 516.2 560.3 5,700 517.3 561.4
5,800 502.2 554.6 5,800 511.4 564.7 5,800 512.6 566.1
5,900 496.5 557.8 5,900 505.6 567.9 5,900 507.8 570.4
6,000 489.8 559.6 6,000 498.9 570.0 6,000 501.3 572.7
6,100 482.1 559.9 6,100 491.9 571.3 6,100 494.7 574.6
6,200 475.6 561.5 6,200 484.5 572.0 6,200 487.8 575.9
6,300 468.1 561.5 6,300 478.2 573.6 6,300 481.6 577.7
6,400 461.8 562.8 6,400 472.9 576.3 6,400 476.4 580.5
6,500 ~ ~ 6,500 467.0 577.9 6,500 471.2 583.2
6,600 ~ ~ 6,600 459.5 577.4 6,600 464.0 583.1
6,700 ~ ~ 6,700 452.5 577.2 6,700 456.1 581.9
6,800 ~ ~ 6,800 445.7 577.1 6,800 447.2 579.1

402CI Build SheetSpecifications not listed are the same as stock. Except as noted, all dimensions are in inches or fractions thereof. All prices sourced through Turn Key Engine Supply, Summit Racing, JEG's, and Scoggin Dickey Parts Center.

Displacement 402ci
Bore x Stroke 4.00x4.00
Compression 11:1
Rod center-to-center 6.125
Piston deck height -0.012
Chamber volume 62cc
Rod bearing clearance 0.0028
Crank endplay 0.004
Piston ring endgap 0.023 top; 0.023, second
Main bearing cap torque 65 ft-lb (moly-lube)
Main bearing/cross-bolt 22 ft-lb (moly-lube)
Rod bolt torque 50 ft-lb (moly-lube)
Head bolt torque 65/70 ft-lb (moly-lube)
Henry's Cost
Manufacturer Part Number Description Price
ARP 243-4317
Head Stud Kit 254
Comp Cams 54-446-11
54-448-11
875-16
13755-KIT
7955-16
XER281HR
XER287HR
R-Series lifters1.75 rocker kit
51/416-inch pushrods
407
(or) 407
246
487
134
Dart 11021122 Pro 1 LS1 1,620
Edelbrock 2908 Victor Jr. LS1 manifold w/module 642
Lunati EA036-395 Rotating assembly 3,584
MSD Ignition 82458 Coil packs 579
  32079 8.5mm Super Conductor wire set 98
Turn Key Engine Supply 12568950
51611
SD7245
12558936
LS2 block
Chrome balancer
Double-roller timing chain
Steel head gaskets
995
280
84
66
  Total $9,476

What's It Flow?

DART Pro 1 LS1
CFM at 28 inches H20
Lift Intake Exhaust
0.200 144 109
0.300 202 154
0.400 254 187
0.500 290 205
0.550 301 210
0.600 313 214

Coast High Performance 406ci StrokerIn short, I felt like the man who takes a knife to a gun fight. But as it turned out, what I needed for this fight was a big 'stick-a really big 'stick. In fact, "Get the biggest dual-pattern cam you can find," was the first marching orders given to me by Coast High Performance's Shawn Mendenhall. Since this Torrance, California-based outfit specializes in building high-horsepower stroker small-blocks, I listened.

Given that the basic architecture of our starting point was created more than 50 years ago, it would be easy to label this contest "space-age versus stone-age." And there's no denying that GM has created an amazing new line of engines. On the other hand, it turns out that spacemen and cavemen have a lot in common when it comes to what's under the hood. Both engines are overhead-valve, pushrod powerplants, which means they're both air pumps. Get the mixture in, burn it, get it out. It ain't rocket science, for a Gen I engine or a whiz-bang Gen IV.

Therein lay our dilemma. The Gen III/IV engines certainly have improved lower ends, but where they really shine is in breathing ability. How would we match up? The rules of this showdown required that all parts be off-the-shelf...so we reached for the top shelf, going with Dart's fully CNC-ported Pro 1 227 heads. These 23-degree aluminum heads are serious breathers, moving 309 cfm at 0.700 inch lift. Dart calls them "professional-quality competition cylinder heads." Using a 400 block as our basis gave us needed displacement and room for the mondo heads to breathe. So there you have our formula: Big bore, big stroke with 6-inch rods, big cam, big heads, and lots of compression and timing make lots of power.

We did just that, and by the numbers we matched the 402ci LS2, and did it on 91-octane to boot. What's striking, however, is how far we had to go to do it. Race heads, a port-matched intake manifold, and one big hairy cam-and that's just for starters. We might go so far as to call this thing a street motor, but someone might ask, "What street?" and we'd be stuck for an answer. It would certainly be one that's driven without power brakes, since that serious 'stick doesn't provide much in the way of vacuum (6.5-7 inches). And as for idle quality...well, let's not discuss idle quality.

All in all, the component parts of the 402 are rather tame by comparison. Yet the total costs were close to equal. Essentially, we had to build a hydraulic-roller race motor to match the new kid on the block, and that we did. At this point in time, old versus new, it really comes down to what you want with your 583 hp. In human terms, one is a svelte gent, a real James Bond, simply charming until he whips out the newest of Q's gadgets and obliterates your ass. The other is a crude brute, swinging wildly from the trees like a Neanderthal until he jumps down and starts beating you over the head with a leg bone from a brontosaurus.

And there's the question of the hour, friends. Spaceman or caveman? Personally, I like 'em both.

Q&A With Shawn Mendenhall From Coast High PerformanceCHP: We gave you a tough task, building a traditional small-block to match up with a Gen IV motor.

Shawn Mendenhall: GM did well in designing the LS-series engines. The 15-degree heads are such a huge advantage. It would have been nice if we could have used 18-degree cylinder heads.

CHP: It there anything to be said for going old school?SM: The only advantage for the 23-degree setup is the bore. With a larger bore size, it's easier for the heads to breathe, and you can start with a factory block, which you can still get at a swap meet. It costs more to do a 4.125-inch bore in the newer motors, because you need cylinder sleeves and custom pistons.

CHP: What does the future hold for the traditional small-block configuration?SM: Until there's no more gas, people will have fun with them. As long as there's a desire for 23-degree parts and people still have stuff stashed in their garages, they're never gonna go away. Aftermarket blocks are more within the average guy's reach.

CHP: You mentioned 18-degree heads. What are your thoughts on the subject? SM: The 18-degree stuff is old-school racing technology. Make it user-friendly, which is already starting to happen, and it's gonna really change the market. You can make good power with 18-degree heads-they're gonna be able to make a ton of horsepower on the street.

Camshaft Specifications

MANUFACTURER Comp Cams
PART NUMBER 12-444-8
TYPE Hydraulic roller
VALVE LIFT 0.562/0.580 inch, intake/exhaust
0.600/0.619 intake/exhaust
(1.6:1 rockers)
DURATION AT 0.050 248/254 degrees, intake/exhaust
LOBE SEPARATION 110 degrees

DYNO DETAILS
Headers 13¼4 Hedman long- Fuel 91-octane unleaded
CAM I Cam I with 1-inch HVH Spacer
Advance 39 degrees Advance 39 degrees
Max torque @ rpm 533.0 lb-ft @ 5,000 Max torque @ rpm 532.7 lb-ft @ 5,000
Max power @ rpm 576.4 hp @ 6,300 Max power @ rpm 582.9 hp @ 6,300
Average torque 485.6 lb-ft Average torque 484.8 lb-ft
Average power 430.8 hp Average power 430.9 hp
RPM lb-ft Hp RPM lb-ft Hp
2,600 401.4 198.7 2,600 386.3 191.2
2,700 399.0 205.1 2,700 386.0 198.4
2,800 398.7 212.5 2,800 387.1 206.4
2,900 401.7 221.8 2,900 392.7 216.8
3,000 408.5 233.3 3,000 403.6 230.5
3,100 419.6 247.7 3,100 417.9 246.6
3,200 433.7 264.3 3,200 432.6 263.6
3,300 445.4 279.9 3,300 445.0 279.6
3,400 456.3 295.4 3,400 456.0 295.2
3,500 465.6 310.3 3,500 465.6 310.2
3,600 473.6 324.6 3,600 474.5 325.2
3,700 481.0 338.9 3,700 481.5 339.2
3,800 488.6 353.5 3,800 487.8 352.9
3,900 495.4 367.9 3,900 492.9 366.0
4,000 501.0 381.6 4,000 497.8 379.1
4,100 505.4 394.6 4,100 502.4 392.2
4,200 510.0 407.9 4,200 506.8 405.3
4,300 514.4 421.2 4,300 512.1 419.3
4,400 518.2 434.2 4,400 516.4 432.6
4,500 521.7 447.0 4,500 519.8 445.3
4,600 525.5 460.2 4,600 523.0 458.1
4,700 529.1 473.5 4,700 527.6 472.1
4,800 531.5 485.7 4,800 530.8 485.1
4,900 532.8 497.1 4,900 532.3 496.7
5,000 533.0 507.4 5,000 532.7 507.2
5,100 532.2 516.8 5,100 532.5 517.1
52,00 530.5 525.2 5,200 531.8 526.5
5,300 528.4 533.2 5,300 530.1 535.0
5,400 525.7 540.5 5,400 527.5 542.3
5,500 522.5 547.2 5,500 524.0 548.8
5,600 519.2 553.6 5,600 520.2 554.6
5,700 515.1 559.1 5,700 516.3 560.4
5,800 510.5 563.8 5,800 512.3 565.8
5,900 505.6 567.9 5,900 507.4 570.0
6,000 500.7 572.0 6,000 503.1 574.8
6,100 493.8 573.5 6,100 498.3 578.8
6,200 487.2 575.1 6,200 492.3 581.1
6,300 480.5 576.4 6,300 486.0 582.9
6,400 470.9 573.8 6,400 477.1 581.3
6,500 456.4 564.8 6,500 462.4 572.2
6,600 441.2 554.5 6,600 446.1 560.6

406CI Build SheetSpecifications not listed are the same as stock. Except as noted, all dimensions are in inches or fractions thereof. All prices sourced through Coast High Performance and Summit Racing.

Displacement 406ci
Bore x Stroke 4.155 x 3.750
Compression 11.1:1
Rod center-to-center 6.00
Piston deck height 0.00
Chamber volume 66cc
Rod bearing clearance 0.0026
Crank endplay 0.006
Piston ring endgap 0.018 top; 0.026, second
Main bearing cap torque 75 ft-lb (moly-lube)
Rod bolt torque 63 ft-lb (moly-lube)
Head bolt torque 75 ft-lb (moly-lube)
JOHN'S COST
Manufacturer Part Number Description Price
ARP 534-9701
134-2501
230-7002
134-5401
230-7002
134-7901
Engine/accessory kit
Harmonic balancer bolt
Head bolts
Main studs
Oil pump stud kit
Oil pump driveshaft
70
19
140
40
7
14
Coast High Performance 406ci Pro Mod shortblock
1.6:1 shaft-mount roller rockers
3,200
Comp Cams SK12-444-8
7609-16
210
XR300HR Small Kit*
Magnum pushrods
2-Piece Billet Aluminum Timing Cover
717
109
220
Dart 11971143 Pro 1 227 CNC 2,574
  68000010 Cast-aluminum valve covers 161
Edelbrock 2900 Victor Jr. port-matched manifold 224
Fel-Pro 1206 Intake gaskets 15
  2812 Full set, thick front seal 100
Hot Rod Performance Oil filter adapter
Fuel-pump block-off plate
Distributor hold-down clamp
20
Milodon 31167 Pro Competition stepped-sump oil pan 345
  18316 Extreme Duty pickup 46
  18750 High-volume oil pump 57
MSD Ignition 85551 Pro-Billet distributor 226
  31359 8.5mm Super Conductor wire set 69
TCI Automotive 87001 Rattler harmonic balancer 280
  Total $9,453
*includes lifters and timing chain

What's It Flow?

WHAT’S IT FLOW?
Dart Pro 1 227 CNC
CFM at 28 inches H20
Lift 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

SOURCE
Coast High Performance
1650 W. 228th St.
Torrance
CA  90501
310-784-2977
www.coasthigh.com
Hot Rod Performance
N/A
High Velocity Heads
N/A
highvelocityheads.com
MSD Ignition
El Paso
TX
9-15/-857-5200
msdignition.com
Milodon
2250 Agate Ct.
Simi Valley
CA  93065
805-577-5950
www.milodon.net
Federal Mogul (Fel-Pro Gaskets)
N/A
federal-mogul.com
Turn Key Engine Supply
7-60/-941-2741
www.turnkeyenginesupply.com
Edelbrock Corp.
2700 California St.
Torrance
CA  90503
310-781-2222
www.edelbrock.com
Automotive Racing Products
1863 Eastman Ave.
Ventura
CA  93003
800-826-3045
www.arp-bolts.com
Lunati
4770 Lamar Ave.
Memphis
TN  38181
901-365-0950
www.lunaticamshafts.com
Dart Machinery
353 Oliver St.
Troy
MI  48084
248-362-1188
www.dartheads.com
Scoggin Dickey Parts Center
N/A
sdpc2000.com
TCI
Ashland
MS
662-224-8972
www.tciauto.com
Demon Carburetion
Dahlonega
Ge
7-06/-864-8544
barrygrant.com
COMP Cams
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