Wednesday, October 21, 2009

Buick 455 Stage 1 Stage 2

Motown Muscle

Occasionally we will run a feature on the engines that powered the muscle car era. These articles may focus on a specific power plant, or sometimes a family of engines. Since it’s a universal truth that muscle car engines are some of mankind’s most noteworthy inventions, we think you’ll dig the series.

First up – Buick 455 Stage 1 and Stage 2:

The folks from Flint didn’t disappoint when it came to performance, although they were a little behind the curve as far as timing was concerned. Their Gran Sport line of cars were on the fringe of the muscle car movement through the middle ‘60s. In 1969, Buick began to get serious with the release of the first Stage I engine package on the GS 400. The ‘69 Stage I featured a healthier camshaft, a 4-bbl Quadrajet with revised calibration and bigger dual exhaust system. This added up to 345 horsepower and 440 lb.-ft. of torque for the 400 cubic inch engine, only 5 hp more than the standard GS 400 mill.

The big news from Buick, though, was the 1970 455 Stage I. The new-for-’70 engine sported a 4.31” bore and 3.90” stroke, but the real differences were found in the camshaft and heads. The camshaft featured .490” lift intake and exhaust, with 316° intake duration and a whopping 340° exhaust duration. The heads received bigger valves; 2.12” intake, 1.755” exhaust, and the ports were worked to increase flow. The compression ratio jumped to 10.5:1, requiring premium fuel to feed the monster. And what a monster it was -- 360 horsepower and a stump-pulling 510 lbs.-ft. of torque. Even in the heavy GS 455 A-body (3800+ pounds), the Stage I provided enough grunt to haul the car through the quarter-mile in the high-13 to low-14 second range straight out of the box. When the Stage I 455 was stuffed between the fenders of the radically styled GSX, Buick’s somewhat uptight image disappeared in a cloud of bright color and tire smoke.

Stage I was only the beginning, however. For more serious performance, Buick developed the appropriately named Stage II package. The components that made up the Stage II package were available over-the-counter only, which means no production cars were built with these items. The heart of the system was the revised camshaft. At .455” intake and .480” exhaust, the lift figures weren’t as high as the Stage I cam, but the duration was much longer at 340° intake and 360° exhaust. The Stage II intake was the aluminum Edelbrock B4B, while Buick engineers tapped the 850 cfm Holley for carb duty. The undisputed star of the Stage II system, though, was the cylinder heads. These heads featured redesigned round exhaust ports instead of the standard rectangular versions. The intake ports were a little different from standard Stage I fare, but the new heads were said to be good for 50 extra horsepower on an otherwise stock engine. Special Mickey Thompson headers that mated to the new exhaust arrangement rounded out the Stage II package.

The Buick Stage I and Stage II programs certainly put the tri-shield brand in the thick of the muscle car wars. And of course fifteen years or so later they once again made American performance history with the turbocharged V6 series of engines in the Grand Nationals and Regal T-Types. Just when you think Buick has relaxed back into their staid persona, they surprise everyone and build a monster. We can’t wait for their next one.


  1. Nice article. I thank you so much for this.

  2. I have a stage 2,,not org motor,,but on the rad. cowl witch is crome the only one I ever seen has a sticker,,gives u the point settings plugs timing,,all the modor info,,cubic inch is 465,,cam shaft is stage 2,,horsepower is 420, torque is 560,,its hard to read,,my gs is a 72,,air cleaner came in the back seat,,also said stage 2 and all the emblems,there all worn,,some say its a kenne belle car. ive read 12 came from the factory,,and 70 special orders came with parts in trunk like yankos,,cant fine any info about it,,just the sticker,,so in my book it was a org stage 2 intill I find info saying its not

  3. I like your post very much:-). Looking forwad fore more. Goog luck!