Buick Engine - Bulldozer Torque
Buick long known for stump pulling grunt are still alive and well, thanksthe the crew at Automotive Machine & Performance
From the February, 2009 issue of Popular Hot Rodding
By Steve Dulcich
Photography by Johnny Hunkins
At the height of the "golden era" of performance, the Buick name brought recognition and status. Unlike today, a world where there is little to differentiate one brand from another, choosing a GM product in the '50s and '60s meant finding your place in the hierarchy. At the top level of opulence and indulgence were the Cadillacs, while the Buick offered prestigious transportation, but at a less ostentatious level. Let the rock stars and celebs drive a Caddy, the Buick owner portrayed success without having anything to prove. Another interesting facet of the era was that, at least at GM, each division designed and produced engines of its own. The engines were as distinguished and unique from the other divisions as was the styling. It was before the time when corporate standardization led to "corporate engines," and Buicks came with a Buick engine, while Chevrolet's powerplants were only found in Chevys. It may seem
inefficient today to consider that GM was producing unique 455 Pontiacs, 455 Oldsmobiles, 455 Buicks, and 454 Chevrolets--four engines within 1 cubic inch of displacement--all at the same time. Thankfully they did, and as a result we can now revel in our favorite big-blocks of the era.
Buick, being a status brand, was highly competitive in the drive to design and manufacture state-of-the-art engines that were both refined and powerful. The seminal "nailhead" OHV engine was introduced in 1953, and it became instantly popular with performance fans in countless applications, from custom hot rods, to Mickey Thompson's four-engine drag wagon. With the cutting-edge overhead-valve nailhead, Buick was rightfully proud of the effortless torque production that was characteristic of a Buick powerplant. Fat low-end torque, and lots of it, was the perfect companion to the easy cruising and powerful Buick style. Buick capitalized on the impressive torque by designating their engines by their prodigious torque production, with names like "Wildcat 455" assigned to the 455 ft-lb 401 nailhead used in the '64 Gran Sport.
By the mid '60s, the nailhead was becoming outdated, and Buick went about designing a new series of engines based upon modern casting techniques and design trends. The result was the "modern" family of big-block Buick engines introduced in 1967. These new and thoroughly modern engines feature major improvements in the cylinder head design, with improved ports and larger valves. The new-design Buick V-8 created power potential far beyond the capabilities of the nailhead.
The pinnacle of the era of Buick performance ushered by the new powerplant was achieved in 1970, when Buick pulled out the performance stops, and stuffed the gargantuan 4.310-inch bore, 3.900-inch stroke, 455 cubic-inch mill into the intermediate GS. The GS455 in that year was available with the mighty Stage 1 455, with a conservatively rated 360 hp at 4,600 rpm, but more notably, an unreal 510 lb-ft of torque, coming in at a locomotive-like 2,800 rpm. This Buick powerplant produced more torque than was available in any production GM vehicle, and that included the best from Chevy, Pontiac and Oldsmobile. In 1970, the Buick was exceeded in outright torque only by the much larger 472 and 500 cubic-inch Cadillac engines, though even these did not match the low-end bulldozer torque of the mighty Buick.
After the high watermark of 1970, the tightening noose of emissions, fuel economy, and insurance regulations saw a progressive decline in the Buick engine. The 455 displacement was dropped after 1976, by which time the output had suffered greatly. The story may have ended there, were it not for the legendary performance of these classic machines. A loyal following of Buick enthusiasts kept the faith with Buick restoration and performance. Interest in Buicks has never waned, and these days it's possible to build Buick power like never before.
Automotive Machine & Performance in Philpot, Ky., is a shop recognized for its expertise in Buick Performance. The company primarily does Buick crate engines, and we were fortunate to have them participate in last year's Engine Masters Challenge, Popular Hot Rodding magazine's annual engine-building competition. Mike Phillips of Automotive Machine had this to say about the Buick's continued popularity: "The Buick makes big horsepower for what it is. It's a small motor compared to the other engines of similar displacement, 50 to 75 pounds lighter than the Ford or Chevrolet big-blocks. The characteristic of the motor is that it was made for an Electra 225, not for racing. The Gran Sports were such popular cars, and there are a lot of them left. Someone is needed to build these motors the way guys want them. Filling that need is what we primarily do." When asked what customers want, Mike replied: "More and more horsepower."
The Buick stroker brought to compete in the Engine Masters Challenge was built for a customer, Mike Bachorsky, for street use in a '70 Buick GS that is currently being restored. This engine's foundation is a factory-production 1976 Buick 455 block. On this particular engine, the bores cleaned up from the factory size of 4.312 inch to 4.325 inch with just a honing. Combined with a 4.325-inch stroke, the basic configuration is square, and displaces 508 cubic inches. Buicks are known for having thin blocks. Mike had this to say: "They are thin. This is a 1976-model block, which is better than the earlier blocks--the bore centers are more consistent. We sonic check all the blocks we build and this one was fairly even in bore thickness. You just have to make sure you start with a good block. The weaknesses are in the main webbing, cylinder bores, and the lifter bores. You have to beef it up everywhere to make it withstand the pressure you put on it."
Mike continued, "T/A performance makes the block girdle that just about eliminates the problem with the main webbing stiffness, but that's not a cure-all for it. We've seen some blocks split right up through the oil hole, right up the cam journal, even with the girdle. We haven't had this kind of failure happen to us." Philips speculates that some of the problem might be in how the block girdle is installed. Automotive Machine seems to have found a technique that works. The secret is in the clearances and consistently setting up and torquing the girdle during all machining operations.
For some engines built with extreme output in mind, block filling can also add a measure of insurance. Mike decided against filling on this engine, "We do it on some engines, and I was kind of torn between doing a partial fill or not. I thought because we only honed the bores and it was near the factory size on the cylinder wall this was a good block to start with, so I did not fill it. This block sonic checked really well for a production piece, with 0.140 inches of wall thickness. Anytime we fill one, we don't do it like we would a Chevrolet, we do what is called a short fill. The way the head bolts are, they go into the water jacket so far--you have to be careful."
Residing in the block is a custom cross-drilled billet crank from Moldex, which is one of the few companies that do a Buick crank. Moldex is equipped with the CNC programs to fabricate these cranks, and considering the Moldex reputation for excellence, they are a fine choice. The crank is, as expected, fully profiled, and features Buick mains, and big-block Chevy rod journals. The rod journal specification allows the use of commonly available aftermarket rods for the Chevrolet application. This engine uses a set of 6.800-inch Eagle H-beam rods, with custom JE 23cc dish reverse-dome pistons, for a compression ratio of 11.3:1. With the Chevy spec rods, the piston pin diameter is also Chevy-sized, at 0.990 inch. The rings are also JE, a set with conventional 1/16-inch widths for the compression rings, and 3/16-inch low-tension oil rings. All the bearings, including the rods, mains, and cam bearings, are coated from Calico.Capping the capable short-block is a set of T/A Stage 2 Track Eliminator heads, which feature a 14-degree valve angle. Buick expert David Wink does all the porting and modifying of the heads, and the result of the effort plays a major role in the engine's output. Wink undertook an intensive development program on these castings, playing with valve sizes to find a combination of 2.250-inch intake and 1.750-inch exhaust valves as the optimal set-up. The fully prepped heads certainly turned impressive numbers, moving a peak of 355 cfm through the intake ports. The induction compliments the high capacity of the heads. An SP2 manifold comes CNC port-matched from T/A Performance and is hand-massaged by Automotive Machine. The finishing touch is a 1095-cfm King Demon carb. Mike reports a peak recorded intake manifold vacuum of 1.1 in-hg at wide-open throttle, recorded at maximum rpm while testing.
Commenting on the heads, Mike informed us, "There's not much you can do with the port because of the pushrod location. You can't widen it on the inside because of the other port, and you can't widen it on the pushrod side because of the pushrod. So what we do is drill out the pushrod hole before we start, and we go ahead and put a brass sleeve in it. That way we can port all the way to the sleeve and we don't have to worry about hitting oil. At the center head bolt, we drill that out and put a .75-inch steel sleeve in it, so when we thin it out we still have the steel. If you thin that thing out too much, you'll actually waffle the intake port, so you have to have the steel in there. We try to keep some swirl in the heads because of the rpm we run the engines at. With these bigger street engines, we usually run no more than 6,500 rpm."
A flat-tappet cam from Lazer Cams operates the valves, and it is a fairly substantial profile, with 266/271 degrees duration at 0.050-inch tappet rise on the intake and exhaust lobes respectively. The cam's action is multiplied by a set of 1.6:1 roller rocker arms from T/A Performance. The combination yields 0.652/0.657-inch lift at the valves.
We were very impressed with the street-bound Buick's 713 hp output, and 667 lb-ft of torque. Considering that the output is achieved with a stock production block, a moderate compression ratio, and a flat-tappet camshaft, it is truly mechanical testimony to back up Buick's reputation.
Automotive Machine & Performance's...
Automotive Machine & Performance's Mike Phillips and David Wink have reason to be proud of their mighty Buick. These guys have earned their reputation as experts with these brawny Buick beasts.
Big-block Buicks are known...
Big-block Buicks are known to be among the most attractive engines when built for performance. Automotive Machine & Performance's 508 cubic-inch version is as powerful as it is beautiful.
The front accessories are...
The front accessories are based upon the OEM configuration, with a remote electric drive for a production-style mechanical water pump. Note the billet oil pump from Scavenger Oil Systems.
In a high-powered application,...
In a high-powered application, the spark has to be reliable, powerful and accurate. Automotive Machine relied on a full compliment of MSD components, including the billet distributor, control box, coil and wires.
The crowning jewel on this...
The crowning jewel on this burly Buick is a King Demon RS carb. The carb capacity was set to 1,095 cfm by installing the appropriately sized venturi sleeves, possible with Demon's unique replaceable venturi system.
The carb feeds a single-plane...
The carb feeds a single-plane intake manifold from T/A Performance, which was in turn modified by Automotive Machine. A 2-inch spacer under the carb adds to the plenum volume, an advantage with the engine's large displacement.
A look inside the plenum reveals...
A look inside the plenum reveals how the intake opening is machined to accommodate the wide butterfly arrangement of the "4500-frame" King Demon. The manifold flange is double-drilled, allowing it to also accept the standard-flanged four barrels.
The proponents of Buick power...
The proponents of Buick power took a huge step forward with the introduction of the Stage 2 Track Eliminator head castings from T/A Performance.
Beneath the valve covers hides...
Beneath the valve covers hides a set of T/A Performance's bulletproof shaft-mounted roller rockers. The ratio is a conservative 1.6:1, but it is enough to boost the flat-tappet cam's lift to over 0.650-inch.
Once the intake manifold is...
Once the intake manifold is removed, extensive epoxy work to the lifter valley comes into view. The flat-tappet cam from Lazer has proven to be reliable, and creates no shortage in outright power.
Between the intake manifold...
Between the intake manifold and the lifter valley is a sheet aluminum heat shield, which separates the underside of the manifold from hot oil splash, saving potentially lost horsepower.
Automotive Machine employed...
Automotive Machine employed serious modifications to bring the intake port cross-section to the maximum size, given the constraints of the Buick's architecture. The pushrod pinch point was sleeved, as was the central head bolt boss, as part of the all-out porting effort.
The chamber side of the T/A...
The chamber side of the T/A heads reveals an open chamber configuration, with a deep, central, plug location. Automotive Machine made the most of the available space with a 2.250/1.750-inch valve combination.
Buttoning up the bottom end...
Buttoning up the bottom end is a fabricated aluminum oil pan from SRE Fabrications. The pan features a built-in windage tray. No further crank windage control was deemed necessary. The pan features a single external pick-up.
The external pick-up from...
The external pick-up from the pan feeds a high-capacity billet oil pump from Scavenger Oil Systems, which feeds oil to a remote-mounted oil filter assembly. The lubrication system performed flawlessly. Mike reports strong oil pressure from idle through maximum rpm.
Adding needed buttressing...
Adding needed buttressing to the relatively fragile stock Buick bottom end is a massive cast-iron lower block girdle from T/A Performance, which ties the mains and pan rails.
Working opposite the chambers...
Working opposite the chambers in the modified heads are a set of custom JE pistons. The pistons are custom JE pieces, with a reverse-dome configuration giving a 23cc dish configuration.
Pulling the pistons out of...
Pulling the pistons out of the bores, we find a conventional high-performance ring package from JE, consisting of 1/16-inch compression rings and 3/16-inch low-tension oil rings. The piston pin is a Chevy-spec 0.990-inch diameter part.
Long 6.800-inch Eagle H-beam...
Long 6.800-inch Eagle H-beam connecting rods help reduce the cylinder loading on the factory Buick block. The rods are off-the-shelf units for a big-block Chevy application.
Looking at the bearings shows...
Looking at the bearings shows the tell-tale black sheen of an anti-friction coating. All of the bearings used in this engine are coated sets from Calico.
|Dyno Results |
|ENGINE SPECIFICATIONS: |
|CID||508 cubic inches |
|Compression Ratio||11.3:1 |
|Camshaft||Lazer solid flat-tappet |
|Cam Duration||266/271 degrees @ 0.050-inch tappet rise |
|Cam Lift||0.652/0.657 inches |
|Rocker Ratio||1.6:1 |
|Lobe Separation||106 degrees |
|Installed Centerline||104 degrees |
|Top Ring||JE moly, 1/16-inch |
|Top Ring Gap||0.020-inch |
|Second Ring||JE 1/16-inch |
|Second Ring Gap||0.022-inch |
|Oil Ring||3/16-inch |
|Piston||JE reverse-dome, 0.990-inch pin |
|Gas Ports||lateral gas ports |
|Quench Clearance||0.040-inch |
|Block||'76 Buick |
|Rods||Eagle 6.800-inch |
|Main Journal||standard Buick 3.250-inch |
|Rod Journal||2.200-inch |
|Cylinder Heads||T/A Stage 2 Track Eliminator, ported |
|Peak Intake Flow||355 cfm |
|Intake valve diameter||2.250-inch |
|Exhaust valve diameter||1.750-inch |
|Intake Manifold||T/A SP 2, ported |
|Carburetor||1095 King Demon |
|Header||T/A Performance 2 1/8-inch |
|Engine Oil||Royal Purple |
|Oiling System||Scavenger |