Big-block Buick engines are known as capable powerplants that produce generous torque at modest rpm. It was a formula that was right on target for smoothly and effortlessly powering the stately, large, and luxurious vehicles from this upscale division of General Motors. The same high-torque approach made for surprising performance when these engines were applied to Buick's notable intermediate GS A-body variants, delivering muscle car performance with a refinement that was a cut above the more raucous competition. Now imagine the potential when any pretense of civility is abandoned, and the quest turns to all-out horsepower. That's just what Mike Philips of Automotive Machine & Performance in Philpot, Kentucky, did when creating the production Buick 455-derived beast featured here.

The engine was built to compete in the Xtreme Street division of our annual AMSOIL Engine Masters Challenge, an engine competition that demands 8,000-rpm dyno pulls and is the realm of exotic all-out competition engines from the ranks of NASCAR and professional drag racing. A production Buick may seem like an unlikely choice for this competitive venue, but Philips had a purpose: “I wanted to show what these Buicks are capable of.”

Adding Beef
The build started with a 1974 production 455 Buick block, a foundation not known for its strength. As Philips tells us: "The Buick block has weaknesses that have to be addressed to make it live in an application like this, and it is neither easy nor cheap to do. By the time we get done with a block like this, the costs are up in the range of some entry-level Chevy or Ford aftermarket blocks." The block beefing starts at the bottom, with the massive main girdle from T/A Performance that ties the mains to the pan rails. The girdle sandwiches the OEM main caps, which are machined to mate with the girdle structure, and tied into the assembly with studs.

Moving upward, the lifter valley area is another vulnerability in the Buick block. Philips explains: “The lifter bores will not accept heavy loading and will break, especially if something goes wrong. We tie this area in with a steel reinforcement and then laminate it with multiple layers of epoxy from the top and bottom.” As a further step toward block longevity in this extreme application, the block received a full fill in the water jackets. Philips tells us: “The cylinder walls are thin, especially between the cylinders. This block was actually found to be cracked, so a full fill was needed.”

As with the block, the crankshaft is also an OEM production unit, and a cast piece at that. While this may seem an unlikely part for a high-rpm race engine, Philips explains, "These stock cranks do not often break, unless they're offset ground to maximum stroke. I did cut the crank to a 2.00-inch pin, but kept the stroke at 3.900 inches. The small journals allowed me to use a set of aluminum rods, and that removed enough weight to let me internally balance the engine. The cast crank is a lot more likely to break with weights bolted on at each end for external balance." The 6.800-inch Manley rods are linked to JE domed pistons with a conventional 1/16-, 1/16-, 3/16-inch ring package, delivering a compression ratio of 14.1:1.

The lubrication system also received extensive modifications to help the engine cope with the intended rpm range. The key player here is a scavenging pump with an external pickup developed by Automotive Machine & Performance. The pump arrangement simplifies the oil path, significantly reducing restriction, and ensuring an ample supply of oil. Internally, the block’s oil galleries were modified by enlarging the drillings, and cutting a blended radius at key intersections. As Philips points out, the dyno information reveals nearly constant oil pressure right up to 8,000 rpm.