Edelbrock's Performer RPM...
Edelbrock's Performer RPM cylinder heads for Buicks can be ordered fully assembled ($947.95 each; Summit pricing), as shown here. Edelbrock also offers a gasket set (which is a great deal as all the gaskets went right on and worked great). We also ordered a set of 3/8-inch-diameter, 9.650-inch-long pushrods from Comp Cams, and their 3/8-inch stud, 1.6:1 roller rockers.
One of the key enablers to building a different engine for your street/strip car is finding a cylinder head that flows plenty of air and fuel, and is widely available. Fans of the big-inch Buick V-8s (mostly the 455) have found the cylinder head issue a tough hurdle to get over...until now. Edelbrock has introduced an aluminum Buick V-8 Performer RPM cylinder head that melds the best design elements of mainstream performance cylinder heads into a Buick cylinder head envelope. Engine builders have commented to us about how this cylinder head bolts on with a minimum of changes to the engine and makes great power, so we decided to learn about installing these new performance heads, and experience the power first hand. To do so, we went to the Buick specialists at White Racing and Marine, in Warren, Michigan, to follow along as they installed and integrated the Edelbrock Buick Performer RPM heads onto an existing street/strip Buick V-8. When the install was over, White Racing picked up 50 hp to the rear wheels on their chassis dyno with the Buick Performer RPM cylinder heads.
The Buick Edelbrock Performer RPM cylinder heads are really what Buick enthusiasts have been waiting for: readily available, solid performing cylinder heads. The number of Buick cast-iron heads available has dwindled dramatically, and many of those heads that are still around have issues, like cracks and rust. And since there was never an aluminum production cylinder head, the Edelbrock head offers an added bonus of reducing the weight over the nose of the vehicle, versus the production cast-iron heads, by 56 pounds!
To do the Buick teardown,...
To do the Buick teardown, refer to a good service manual and ask a buddy or two to help out. Doing a head swap requires the front accessory drive, fuel, coolant, exhaust, and intake systems to be removed from the vehicle. Make sure to mark everything as you remove it. Also, a good idea is to take digital photos to make the install easier. Drain the coolant out of the block by removing the lower block plugs to avoid coolant drooling into the cylinders when you remove the heads.
These Edelbrock Performer RPM heads are designed for street/strip high-performance use on '67-81 400-, 430-, and 455ci Buick V-8 engines (you need at least a 4.040-inch bore diameter to use these heads). They work well between 1,500 and 6,500 rpm, which should be great for the vehicle being upgraded in this story. Many would classify our guinea pig car as a Saturday-night special, with its Dyers blower, loose B&M converter, and DOT-legal Mickey Thompsons.
Like some of the other Performer RPM heads from Edelbrock, the Buick version uses 3/8-inch stud-mounted Chevy small-block rockers. (We ordered a set of 1.6:1 ratio rockers from Comp Cams, and they worked great.)
By designing these heads to use one of the most common and proven valvetrain designs, Edelbrock has minimized the valvetrain costs (and eliminated the need to use the expensive shaft-mount rocker systems) while providing optimal performance and durability. The Performer RPM heads come with special Edelbrock pushrod guideplates that are set up for 3/8-inch-diameter pushrods. Edelbrock recommends ordering pushrods that are 9.650 inches long; we ordered this length pushrod from Comp Cams (which is an off-the-shelf item for them) and they provided optimal valvetrain geometry on the 455 Buick being upgraded here.
The Buick Performer RPM heads feature a 68cc wedge-style combustion chamber, 2.125-/1.750-inch intake/exhaust stainless steel, one-piece, swirl-polished valves with undercut stems for increased flow. The Performer RPM heads also have performance-enhanced intake and exhaust ports (215cc and 130cc, respectively) that line up with the mounting locations for the production intake and exhaust systems. The heads feature an enhanced 5/8-inch-thick deck surface to be able to handle impressive power without any sealing issues.
The heads might require a...
The heads might require a little pry to free them from the engine block--but if it is any more than a light push, recheck that you have all the head fasteners out before really prying hard on anything. Next, remove the head studs (shown), which need to be removed to properly clean the deck surface of gasket material. This is done by tightening two nuts together and applying torque to the lower nut. All studs should have their threads cleaned of thread sealer and the threads chased to make sure they thread back in clean.
Edelbrock does offer an aluminum Performer RPM intake manifold and carburetor system that works well with these heads, but the Buick engine being upgraded for this story has a hand-built blower intake (hey, if you're going to be different in your engine package, you might as well go all the way, right?), so this engine will stick with the intake/blower system it has been running.
The spark plug location is also in the stock location on the Buick Performer RPM heads, but uses a 14mm thread pitch, -inch reach, 5/8-inch hex, and a gasketed-seat spark plug. White Racing recommends an Autolite 3924 spark plug, gapped to 0.032 inch on the Performer RPM heads.
You can purchase the Buick Performer RPM heads assembled with valves, valvesprings, retainers, and guide plates for 3/8-inch pushrods, or as a machined casting. We ordered the heads fully assembled for this engine because the existing valvesprings were worn out and would have needed to be replaced anyway.
The installation process that White Racing performed included inspecting and prepping the new cylinder heads, doing a mock install with some Comp Cams checking valvesprings installed on one cylinder to check valve-to-piston clearance and valvetrain geometry, checking that all the cylinder head studs were properly installed (an Edelbrock-recommended procedure for these engines) and then installing the heads.
In the end, the upgrade netted a peak-to-peak increase of 48 hp (and up to 57 hp at one point in the power curve), which is pretty much about everything one could ask for when making a cylinder head upgrade.
|STUFF YOU'LL NEED |
|DESCRIPTION: ||SOURCE: ||PART NO. ||QTY.: |
|Cylinder heads ||Edelbrock ||60049 ||2 |
|Gasket kit ||Edelbrock ||7369 ||1 |
|Pushrods (9.650-inch) ||Comp Cams ||7658-16 ||1 set |
|Adjustable 1.6:1 rockers ||Comp Cams ||19002-16 ||1 set |
The really early big Buick...
The really early big Buick V-8s had a pressurized oil feed hole for their shaft rocker system that came up through the deck of the block near the front of the engine. The Edelbrock heads use a small-block Chevy-style valvetrain that feeds oil through the pushrods to the top of the engine, so the oil-feed hole needs to be blocked off on early Buicks. White Racing plugged this oil feed hole with a 0.35-inch aluminum plug.
|WEIGHT COMPARISON |
|Edelbrock aluminum: ||33.3 lbs |
|Stock Buick cast iron: ||61.0 lbs |
|Total weight savings: ||56 lbs |
On The Dyno
This supercharged 461ci Buick is not built to go racing, but it is built to look and sound like it is built to go racing...while still being somewhat docile enough to drive around town. With that said, this engine combination produces good power, but getting the dyno to record those numbers was difficult, as this engine is backed by a 5,500rpm stall converter that would not fully hook up until about 5,700 rpm, so the chassis dyno results capture a very narrow portion of the engine's rpm band. They do, however, give a good snapshot of the gains that came from the Edelbrock Performer RPM heads, and leave us looking forward to letting this engine sing at wide open throttle (WOT) on a warm summer Saturday night.