540 Chevy Big-Block Engine Build - Toeing The Line
Speed-O-Motive Builds A Powerful Pump-Gas 540CI Street Warrior
From the March, 2009 issue of Chevy High Performance
By John Nelson
Photography by John Nelson
It's good to know what you want when you set out to build an engine. It's even better to actually get it.
As Ken Sink formulated a replacement Rat motor for his original big-block-powered '68 Chevelle SS, he wanted two things: torque and fun. It's a concise set of goals, especially since in a street car, the two are synonymous. There's a sure way to achieve lots of fun-inducing grunt, and that's with a big bore and a long stroke. Accordingly, Sink turned to Speed-O-Motive to create a muscular yet very reasonable 9.4:1 540ci fat-block. The result is a powerplant that will tolerate any type of pump-gas swill, handle anything from around-town cruising to a cross-country journey, and make a grin-inducing 659 hp and 620 lb-ft of torque while doing it.
The basis for this big-block creation was a GM Gen VI block. This piece, which is the basis of GMPP's 502 crate motors, has a number of advantages when creating this type of big-bore, big-stroke combo. Right off the bat, it has four-bolt mains and will clear up to a 4.500-inch stroke. The Gen VI block also has Siamesed bores. Put simply, this means there is thicker wall material with no water jackets between the cylinders, allowing for bores as large as 4.500 inches in diameter.
Sink set out to make the combo bulletproof, teaming the four-bolt mains with a Speed-O-Motive forged steel crank, Carrillo forged H-beam rods, and JE forged flat-top pistons. The bore-by-stroke dimensions to create 540 ci are 4.500 by 4.250 inches. It's a good combination, simply because it has more of everything. More stroke equals more torque. Bigger bore equals more power. And with a 9.4:1 compression ratio, this thing will most likely even run on California 87-octane without complaining.
While a lower end certainly costs plenty of change, the single biggest investment a big-block builder will make is the cylinder heads. Sink chose a set of Brodix Race-Rite BB-R series lungs, and they proved to be ideally matched to the rest of the combo. These heads flow plenty, as you can see in the accompanying chart, but the 294cc intake ports also maintain good air speed, meaning torque levels and low-rpm throttle response are also good. The RRs also have their exhaust ports in the stock location, so header installation in the '68 Chevelle won't be a problem. They're also drilled to accept factory-style brackets, so outfitting the new engine with accessories will be problem-free as well. In fact, except for the fact that a Gen VI block has no provision for a mechanical fuel pump, Sink figures that no one looking under the hood will be able to tell the difference between the original Rat and his new 540 brute.
In accordance with the "able to be driven anywhere" ethos Sink followed for this engine, moderation was the name of the game when it came to the camshaft. A Comp solid roller got the nod, so occasional valve lash settings are really the only (small) hitch in this mule's leave-it-alone, plug-and-play guise. In our book, the cam plays to the strength of the heads with its 0.653/0.660-inch intake and exhaust lift figures. These specs take full advantage of the heads' excellent flow numbers, getting as much mixture into the cylinders are possible. On the other hand, the cam's 248/254-degree duration figures are fairly moderate. So while this engine definitely makes good horsepower (659 at 6,200 rpm), it has a very broad torque band, averaging 556 lb-ft from 3,200 to 6,500 rpm.
On the one hand, there's no doubt that this 540 combo could make loads more power. One indication of that is the massive 54 lb-ft average torque gain we saw by adding more intake plenum space with a 2-inch open spacer; this one's a no-brainer for this engine. The other indication is the moderate cam, creating a powerband that's done by 6,500 rpm. This thing could certainly make beaucoup horsepower with a more-aggressive 'stick. On the other hand, that would defeat the whole purpose of the thing. "I don't need a screamer," Sink explained. "This is kind of a reasonable motor to build, and the whole goal is just fun." Oh, and don't forget about the torque. With what this 540 has on hand, we don't think the fun part will be a problem.
What We Did
Followed along as Speed-O-Motive built a serious street 540 big-block
There's grunt to spare on tap, and plenty of horsepower to go with it.
The reciprocating assembly...
The reciprocating assembly consists of Carillo 6.385-inch forged H-beam rods and JE forged flat-top pistons. With a zero deck height and -3.0cc piston dome value, compressions is a run-on-anything 9.4:1.
Speed-O-Motive's Bill Shoemaker...
Speed-O-Motive's Bill Shoemaker had most of the 540 together when we arrived. Using the proper ring compressor, Shoemaker carefully tapped the last piston into place with a soft, brass-tipped hammer handle.
With the last piston in place,...
With the last piston in place, Shoemaker flipped the engine over and torque the last rod cap into place, giving it 75 ft-lb with moly lube. This view also reveals the Gen VI block's sturdy flour-bolt mains and the Milodon one-piece oil pan gasket we used.
The Gen VI block uses a one-piece...
The Gen VI block uses a one-piece rear main seal. This shot also shows the Melling high-volume oil pump and the Milodon louvered windage tray, installed with standoff bolts.
With the bottom end complete,...
With the bottom end complete, Shoemaker bolted the Milodon oil pan into place. This 7-quart pan has an 8.5-inch sump and is designed to fit into almost any Chevy chassis, including the '68 Chevelle this engine is destined for. It also has internal oil control baffles, as well as notches to clear up to a 4.500-inch stroke.
Shoemaker put the Comp solid...
Shoemaker put the Comp solid lifters in an oil bath to ensure proper lubrication at startup, then slid them all into place.
Besides providing excellent...
Besides providing excellent flow figures, Brodix Race Rite heads are drilled to accept stock accessories and brackets; the exhaust ports are also located in the factory location, making manifold or header installation a snap. From a performance standpoint, the RR BB-R heads are CNC port-matched and bowl blended, and feature a competition valve job.
Our bumpstick for this project...
Our bumpstick for this project was a Comp XR282R solid-roller, sporting 0.653/0.660-inch lift and 248/254 degrees durations. The cam card called for installation to be on a 106 intake centerline-Shoemaker degreed the cam and found that it spec'd in at a 105-degree intake centerline. We call it close enough, especially after the timing chain stretches a bit.
According to GM, Gen VI blocks...
According to GM, Gen VI blocks feature a reinforced deck surface for better sealing. To use Mark IV heads on a Gen VI block, the proper gasket must be used-in this case, we employed Fel-Pro 1075 MLS gaskets.
In addition to its CNC gasket-matched,...
In addition to its CNC gasket-matched, 294cc intake ports, Brodix's Race Rite BB-R heads feature 119cc CNC bowl-bended combustion chambers.
Shoemaker fastened the Brodix...
Shoemaker fastened the Brodix lungs in place with ARP head bolts, using moly lube on the threads and under the washers. Torque was 70 ft-lb. When one is using MLS gaskets, Shoemaker told us, final torque needs to be rechecked several times, since the gasket may move as many as four times before it takes a set at the final torque value.
Once the heads were bolted...
Once the heads were bolted into place, Shoemaker set up the pushrods and rocker arms on one cylinder to check piston-to-valve clearance. Shoemaker does this by bringing the piston up to TDC, zeroing the dial gauge, then tightening the rocker bolt and compressing the lifter until the valve touches the piston. We had more than 0.130 inch clearance on the intake side and more than 0.155 inch on the exhaust.
We used Manley rocker studs...
We used Manley rocker studs and pushrod guides as the foundation for our valvetrain. Shoemaker noted that the stud holes in this setup aren't blind, and therefore need to be coated with thread sealant.
With our Manley pushrods and...
With our Manley pushrods and Comp Pro Magnum 1.7:1 rocker arms in place, Shoemaker set the valve lash. The hot setting on the cam card is 0.016/0.018-inch intake/exhaust. Shoemaker set the cold lash 0.006 tighter (0.010/0.012 inch) to compensate for the expansion that will happen as the engine heats up. The lash was rechecked once the engine reached operating temperature, of course.
The holes are used when installing...
The holes are used when installing an OEM intake manifold. They weren't used in our setup, so Shoemaker filled them up with some silicone before putting the intake gaskets in place.
Using some Gasgacinch to make...
Using some Gasgacinch to make sure they stayed put, Shoemaker set the Fel-Pro 1275 intake gaskets in place. The heads are port-matched to a Fel-Pro 1211 gasket, but they lined up well with the 1275s as well.
Intake manifold of choice...
Intake manifold of choice was a Professional Products Hurricane, which has 1.69x2.31-inch ports, which works with either a Fel-Pro 1211 or 1275 gasket.
Carburetion duties were handled...
Carburetion duties were handled by a Holley 1000 HP mixer-best results were achieved with a 3-inch Trans-Dapt open spacer. Fires were lit by a tried and true MSD Pro Billet distributor. On the dyno it was teamed with a Digital 7 box.
Speed-O-Motive's Rick Craven...
Speed-O-Motive's Rick Craven ran in our newly minted 540 and brought it up to temp on the dyno. After rechecking valve lash, he let 'er rip. The factory 84/88 jet combo put us right where we needed to be for this street-oriented motor, even after we added the spacer.
What's next for this torquey...
What's next for this torquey 540? It'll pull duty in an original '68 big-block Chevelle, where the whole goal, the car owner told us, is to just have fun. With 659 peak horsepower and 566 average lb-ft of torque on tap, this thing should provide fun galore.
|WHAT'S IT FLOW? |
|BRODIX RR BB-R HEADS |
|Valve Size ||0.200 ||0.300 ||0.400 ||0.500 ||0.600 ||0.650 ||0.700 |
|2.250 intake ||160 ||226 ||276 ||314 ||337 ||341 ||342 |
|1.880 exhaust ||116 ||145 ||172 ||196 ||217 ||230 ||236 |
|CAM SPECS ||540CI BUILDSHEET |
|Manufacturer ||Comp Cams ||Displacement ||540 ci |
|PN ||11-772-8 ||Bore x Stroke ||4.500 x 4.250 |
|Grind Number ||XR286R ||Compression ||9.4:1 |
|Type ||solid roller ||Rod Center-to-Center ||6.385 inches |
|Valve Lift ||0.653/0.660-inch, intake/exhaust ||Piston Deck Height ||0.000 |
|Duration at 0.050 ||248/254 degrees, intake/exhaust ||Chamber Volume ||119 cc |
|Lash (hot) ||0.016/0.018, intake/exhaust ||Rod Bearing Clearance ||0.0025 |
|Lobe Separation Angle ||110 degrees ||Crank endplay ||0.0075 |
| ||Piston Ring || |
| ||Endgap ||0.021 top, 0.018 second |
| ||Main Bearing Cap Torque ||100 ft-lbs (moly lube) |
| ||Rod Bolt Torque ||75 ft-lb (moly lube) |
| ||Head Bolt Torque ||70 ft-lb (moly lube) |
|PARTS LIST |
|MFG ||PN ||ITEM |
|ARP ||135-3701 ||Head bolts |
|135-2001 ||Intake manifold bolts |
|100-7504 ||Valve cover bolts |
|200-2401 ||Carb bolts |
|Brodix ||RR BB-R ||Assembled rectangular-port cylinder heads |
|Carillo ||C-427>-76385H ||Forged H-beam rods |
|Comp Cams ||1320-16 ||Pro Magnum roller rockers, 1.7:1 ratio |
|11-772-8 ||Solid roller cam |
|897-16 ||Solid roller lifters |
|Federal Mogul ||1075 ||Head gaskets |
|1275 ||Intake gaskets |
|Z2920 ||One-piece main seal |
|GM Performance |
|Parts ||10237292 ||Gen VI Block |
|Holley ||80514-1 ||1000 HP carb, annular boosters |
|JE Pistons ||257965 ||Flat-top pistons, -3.0 dome volume |
|Mahle Clevite ||MS 829 H ||Main bearings |
| ||CB 743 H ||Rod bearings |
|Manley Performance |
|Products ||25835-8 ||8.350-inch pushrods |
|25940-8 ||9.400-inch pushrods |
|42288 ||7/16-inch rocker studs |
|42164 ||pushrod guides |
|Milodon ||84510 ||Balancer bolt |
|85680 ||Breather |
|22010 ||Dipstick |
|30955 ||Low-profile oil pan |
|81137 ||Main studs, with windage tray |
|41002 ||One-piece oil pan gasket |
|81151 ||Oil pan studs |
|18760 ||Oil pump |
|18201 ||Extreme-duty pick-up |
|14875 ||Timing cover |
|15055 ||Timing chain |
|85600 ||Valve covers |
|32200 ||Windage tray, louvered |
|MSD Ignition ||95551 ||Pro Billet distributor |
|31379 ||Super Conductor wires |
|Professional Products ||53030 ||Hurricane intake manifold, rectangular port |
|90005 ||PowerForce+Plus harmonic damper |
|Speed-O-Motive ||SOM-3-454B ||4340 forged steel crank |
|Trans-Dapt ||2461 ||2-inch plastic spacer |
|DYNO DETAILS 1 |
|Headers ||Dawson 2 1/8-inch long tubes |
|Advance ||36 degrees |
|Fuel ||91-octane unleaded |
|Carb ||Holley HP 1000 |
|Jets ||84/88 with 6.5 power valve |
|Max Torque @ rpm ||619 @ 4,600 |
|Max Power @ rpm ||645 @ 6,200 |
|Avg Torque ||512 |
|Avg Power ||346 |
|DYNO DETAILS 2 |
|Headers ||Dawson 2 1/8-inch long tubes |
|Advance ||36 degrees |
|Fuel ||91-octane unleaded |
|Carb ||Holley 1000 HP |
|Jets ||84/88 with 6.5 power valve |
|Other ||2-inch Trans-Dapt open spacer |
|Max Torque @ rpm ||620 @ 4,200 |
|Max Power @ rpm ||659 @ 6200 |
|Avg Torque ||566 |
|Avg Power ||383 |