Small Block Chevy Engines - 3-Way Small-Block Showdown

3 Staffers, # Builds, and a Whole Lot of Bench Racing

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Building engines and having the ability to pull them on the dyno is by far one of our cooler moments as automotive scribes. In this instance, rather than doing a single buildup we assigned each staffer to build a motor for a three-way small-block shootout. The rules were simple: You could only spend $5,500. There were no limits to cubic inches, any camshaft could be used, and everyone had to account for every last coin spent.

It may sound easy; however, in order to build a respectable motor you better do your homework. Slapping a hodgepodge of components together will get the job done, but it doesn't necessarily mean it'll run the numbers. Think about it. Big cams are cool, but they also need to be in sync with the intake manifold and cylinder heads you're using. Then there's the static compression. In most cases, unless you're going blown, compression is your friend. Unfortunately, depending on your particular combination, you won't always be able to get what you want with out-of-the-box pieces and you may have to mill your heads, which can take additional money out of your already limited budget.

Now, what makes this story so compelling is that the individuals involved in these builds have varied personalities. If you had to label us, senior editor Bob Mehlhoff is more of a resto guy who can appreciate power but is generally more concerned about drivability, whereas associate editor John Nelson gets his kicks from flogging high-rpm cars at open-track events. Then there's me, a drag racer at heart who couldn't care less about idle quality and low-idle vacuum. Was there a clear-cut winner? That all depends on what you like and what you expect out of your motors--so you'll have to tell us. You'll find that we've highlighted each engine's peak numbers and included the average horsepower and torque figures, along with complete price sheets detailing every component used. As an added bonus--and to make things a little more interesting--we added a Nitrous Works single-stage nitrous system to the mix. Did anyone blow up? Better read on to find out.

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NITROUS WORKS!
The greatest and cheapest equalizer available is nitrous! Nitrous Works' entry-level, single-stage plate didn't quite fit into our budget, but we would be fools for not subjecting our dyno rats to a little testing. This system retails for $413.99 and is good for an additional 75-200 hp at the touch of a button.

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EXTRA CARB DIET
Holley says that the Street HP carb uses the best features from the 4150 HP but is tamed for street use. This 750-cfm mixer is fitted with mechanical secondaries and adjustable air bleeds, among other features. Very little dialing in was needed.

Squeaker Mouse 355ci
Needless to say, there was a lot of jaw jacking going on in the office as we were all trying to pin down the stroker motors. Let's face it, if you're going to build anything based off a small-block 350, a stroker kit is really the only way to go. Right? In this instance, while I wanted to go with the cubic inches, I took a step back and decided to try the opposite end of the spectrum. Knowing that the lack of cubic inches would put me at an immediate disadvantage, I wanted to go for a peaky motor, one that could easily buzz up to 7,000 rpm and wouldn't be afraid to take a nitrous hit.

To get the job done, I talked with Coast High Performance in Torrance, California. Rather than starting with a junkyard block, I took full advantage of its 355ci short-block. The base Street Fighter SS short-block starts at $1,899, but I kicked it up a notch and went with the Street Fighter for $2,300, which includes a set of CNC Beam forged-steel connecting rods and full-floater SRS forged pistons.

While I'll let the parts list and performance numbers speak for themselves, you'll notice there are two dyno numbers, representing the 725-cfm Road Demon and the 750-cfm Mighty Demon. The Road Demon made the budget, but our little 355ci commanded more fuel for our particular combination. While the numbers were respectable by all means, simply switching over to a 750-cfm Mighty Demon netted us an additional 7 hp and 17 lb-ft. The reality is if we were to take full advantage of the larger carb it would have placed us over the budget. Not terrible, but at least you have the facts.

As for what I would do with this bullet--slap it in a chassis car weighing 3,200 pounds in front of a TH350 and steep gears, and it would make for one fun Saturday night special. 12s would be a walk in the park and on the unit, and it's anyone's guess but mid-10s wouldn't be unreasonable. I am eyeing a '73 Camaro, so we may have to test that theory out in a future issue.

4

Our Coast High Performance 355ci short-block included a set of forged SRS pistons, which easily withstood the added pressures of nitrous. Our pistons were -0.012 in the hole, which decreased our compression slightly, making it pump-gas friendly at 10.25:1.

Here's a quick tip: Most aftermarket timing chains are notorious for rubbing against the block. Our engine builder, Jun, went ahead and machined the problematic area, eliminating any potential metal shavings from entering the pan and oiling system.

If you want to save a few bucks, Coast High Performance also offers a press-fit 5140 forged connecting rod. As part of our upgrade, we included these CNC Beam forged 5.700-inch rods and ARP bolts.

To save a little, we opted for the RHS as-cast 200cc aluminum heads. Depending on your combination and funds, RHS also offers a CNC option with intake runners varying from 185cc to 235cc and various combustion chamber sizes, including a set of budget-friendly cast-iron heads.

Coast High offers most of its completed short-blocks in a two-bolt main configuration, but you can upgrade to the four-bolt main like ours--be sure to call for current pricing. For added insurance we utilized ARP fasteners on everything including the rods, mains, heads, and manifold, and even used a complete dress kit for the oil pan, oil stud, and timing cover.

Up top, we used a Professional Products single-plane manifold, a Comp Cams valvetrain (including rockers, pushrods, and lifters), and a set of Fel-Pro 1010 head gaskets and 1205 manifold gaskets. The single-plane design was instrumental when we sprayed the 175-shot of nitrous.

Swapping from a 725-cfm Road Demon to a 750-cfm Mighty Demon gave us an additional 17 hp and 71 lb-ft, but took us $194.96 over budget.

Prior to mounting, Jun applied a small bead of silicone inside the balancer to ensure a solid, leakproof assembly.

Henry's HookupsARP
800.826.3045
arp-bolts.com

Coast High Performance
310.784.1010
coasthigh.com

Comp Cams
901.795.2400
compcams.com

Demon Carburetion
706.864.8544
barrygrant.com

Federal Mogul (Fel-Pro Gaskets)
248.354.7700
federal-mogul.com

Milodon805.577.5950
milodon.com

MSD Ignition
915.857.5200
msdignition.com

Nitrous Works
706.864.8544
barrygrant.com

Pertronix Performance Products<
909.599.5995
pertronix.com

Professional Products
323.779.2020
professional-products.com

Racing Head Service
901.259.1134
racingheadservice.com

Summit Racing
800.230.3030
summitracing.com

TCI Automotive
888.PRO.XTCI
tciauto.com

383ci Stump Puller
There's nothing like being put on the spot to make a guy define his priorities. Case in point: getting two weeks to spec out and create a $5,500 small-block. Actually, it didn't take much more than a few minutes for a list of desirable qualities to crystallize in my sleep-deprived brain. Right off the bat, I wanted an engine I could actually put to use: street, strip, autocross, open-road racing. A dyno bullet would not do. Second, I've been enamored of the Gen III LS6's powerband since my first drive in a Z06, so I was looking for a Kansas-flat torque curve with a horsepower peak to match. Getting into the 450-plus range for each would be good--higher than that would be better.

Third--and this was the curveball--I wanted this engine to be capable of passing at the pipe if I decided to slip it under the induction system of an '80s smog car. Not that I endorse that kind of thing, mind you. But it's an interesting exercise...

The recipe, as I saw it, called for a stout but not over-the-top bottom end, a heavy-breathing top end, and as much cam as we could get away with. The cam and heads combination proved to be key. Dart's 215cc Iron Eagle Platinum Series heads are relatively inexpensive, but the flow numbers they generate make them an outright bargain. We chose a Comp hydraulic-roller cam for long-term reliability, but the chosen 'stick would have to make the most of the heads' efficiency. Our duration figures are fairly stout for a street cam, and the lift numbers are up there, but keeping the lobe separation at 113 degrees allows for adequate vacuum and a livable idle, and makes the engine relatively emissions friendly.

Relying heavily on the knowledge and experience of Speed-O-Motive's George Ullrich, my LS6-style traditional small-block became a reality. The peak numbers of 470 lb-ft and 458 hp are about as close to equal as you can get--more importantly, this baby is making more than 400 lb-ft from 2,500 rpm all the way to six grand. Acceleration on demand throughout the powerband, but plenty of horsepower for top-end haulin'--this engine would make a good-handling car an utter riot to drive. And isn't that the whole purpose of building a hot engine?

4

Speed-O-Motive bases its heads on bare castings, which are machined before assembly. In our case, this meant taking a couple of thousandths off the surface of our 215cc Dart Iron Eagle Platinum heads. The heads were then assembled with Manley valves and seals, along with cam-matched Comp springs and valvetrain components. The Dart heads feature machined spring pockets, but S-O-M uses locators for improved durability.

We used S-O-M's forged rods, which were all balanced to within 0.5 g of the lightest piece. What kind of weight is that? A dollar bill weighs 1 g. That's tight.

Since we used a hydraulic-roller 'stick, a cam button was needed. Bill ground strategically placed flats into the button to ease installation--and removal--for adjustment to 0.003-inch endplay.

Mahle's Power Pak pistons are exquisite forgings that look almost too nice to put in an engine. Each slug was also balanced to within 0.5 g of the lightest. Finding the best place to take material from required some careful measurement.

Although we ordered the specified Comp Cams pushrods for our application, Bill still checked for proper valvetrain geometry before installing our rocker arms. These lines across the center of the valve indicate that we're right on.

We used S-O-M's steel roller rocker arms. Going to a 1.6:1 ratio increased our cam lift to take advantage of the deep-breathing Dart heads.

If you've never strapped your own engine down to a dyno to see what's what, we highly recommend the experience. The only thing better than seeing it is running it.

ARP
800.826.3045
arp-bolts.com

Comp Cams
901.795.2400
compcams.com

Dart Machinery
248.362.1188
dartheads.com

Federal Mogul (Fel-Pro Gaskets)
248.354.7700
federal-mogul.com

GM Performance Products
gmgoodwrench.com

Hamburger's Performance products
562.921.0404
hamburgersperformance.com

Holley Performance Products
270.782.2900
holley.com

Mahle Motorsports
888.255.1942
mahlemotorsports.com

Nitrous Works
706.864.8544
barrygrant.com

Pertronix Performance Products
909.599.5995
pertronix.com

Professional Products
323.779.2020
professional-products.com

Specialty Auto Parts (Proform)
586.774.2500
proformparts.com

Speed-O-Motive
626.869.0270
speedomotive.com

396 Torque MonsterIf you're an avid Chevy High reader, we're sure you'd relish the chance to get a bankroll of $5,500 to build your own small-block to your specs. For this opportunity I decided to build something other than what we've built over the last few years. The target performance range of this motor is something that will easily produce lots of torque and work very well in a street-driven performance car. That meant a completely different displacement, a not-so-often-tried camshaft, and a set of low-cost aluminum cylinder heads. The shop I chose to accomplish this engine build was Larry's Performance in Montebello, California.

For many, the term 396 conjures up thoughts of a stout big-block Chevy, but in this case all 396 ci are stuffed into a four-bolt-main 350 Mouse block. This buildup started with a well-worn '79 Chevrolet small-block casting that had been pulled from a half-ton truck and bored 0.030-inch over to achieve a 4.030-inch cylinder. The large displacement from the 350 motor is achieved by axing the stock 3.48-inch stroke crank and replacing it with a 3.8750-inch forged-steel shaft fitted to a set of 6.00-inch I-beam full-floating rods and SRP forged pistons. Yes, this means a very short 1.062-inch compression height on the pistons.

To support the midrange power goal of this combination, an Isky 292 Mega cam with 505-inch lift, 244 degrees of duration (measured at 0.050-inch lift), and 108-degree lobe center got the nod. The ignition system is a proven MSD unit and MSD ignition wires. Then a set of aluminum cylinder heads to help lighten the load and a Professional Products dual-plane intake topped off the package to provide good engine performance within the budget.

When we had finished we were rewarded with a big 481 lb-ft of torque on the dyno and almost 440 horses. Yes, big power for little money.

4

The secret of this large-displacement engine is the forged-steel crank with 3.8750-inch stroke, which translates to a 0.395-inch increase in stroke. Thoroughly clean any crankshaft before installation (even if new).

After installing all the main bearings and measuring the clearances, the long-stroke crankshaft was dropped into position.

For good midrange power we added an Isky 292 hydraulic Mega Cam. This bumpstick is ground on a 108-degree lobe center and has 0.505/0.505-inch lift. Key to proper cam installation is the addition of the manufacturer's lube. This provides adequate camshaft lubrication during the first few moments of engine operation, before engine oil reaches each lobe.

The pistons selected for this 396 small-block are full-floating SRP forged items connected to 6-inch I-beam rods.

Each piston and rod assembly is quickly pushed into the bore with the help of a ring compressor seated squarely to the deck of the block. To do this properly each respective crank journal must first be placed at bottom dead center.

With the reciprocating parts installed we measured the deck height. This configuration provided 0.015-inch above the piston at TDC.

Each connecting-rod side clearance measured about 0.020-inch.

To secure the heads to the motor we first applied the appropriate lube and torqued our ARP head bolts to 65 psi.

With the short-block together we installed the aluminum cylinder heads provided by Larry's Performance. These heads have 195cc intake ports and 2.02/1.60-inch valves.

Included with this engine package is a full set of 1.5 stainless roller rocker arms.

To help our midrange power goal we added a Professional Products dual-plane intake manifold. To ignite the motor we also installed an MSD ignition system.

Together and on the dyno took in a matter of days. The carburetor we chose for this combination is a Barry Grant 750-cfm Mighty Demon. Before our initial start-up we added 5 quarts of Rotello 15-40 engine oil for proper camshaft break-in.

ARP
805.339.2200
arp-bolts.com

Barry Grant
706.864.8544
barrygrant.com

Isky Racing Cams
323.770.0930
iskycams.com

Larry's Performance Shop
323.722.8865
larrysperformance.com

MSD Ignition
915.857.5200
msdignition.com

Professional Products
323.779.2020
professional-products.com

COMMENTS

TO TOP
With Nitrous
RPM lb-ftHp
3,000392.7224
3,100393.9232
3,200396241
3,300401.2252
3,400406.3263
3,500414276
3,600426.5292
3,700441.8311
3,800446.2323
3,900447.4332
4,000452.6345
4,100452.7353
4,200465.4372
4,300482.3395
4,400662.6555
4,500653.3560
4,600644.8565
4,700632.5566
4,800622.6569
4,900613.4572
5,000605.8577
5,100594.4577
5,200585579
5,300572.1577
5,400561577
5,500422.2442
5,600410437
5,700396.9431
5,800384.7425
5,900376.4423