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The compression height is 1.975, the stock rods are 6.600 inches, the stock stroke is 3.900 inches, and the production deck height is 10.57 inches.That adds up to pistons that are 0.045 in the hole, but JMS decked the block 0.005, so the real-world number is a poor 0.040 below the deck.
Work those numbers with the 70cc chambers in the iron heads used this month and the compression ratio is just 8.77:1.Both Eddie units were dual-planes, and both TA castings were single-planes.Interestingly, we inspected the two Edelbrock intakes and the only difference we could see in them was the shape of the carb pad and the fact that the Performer places the carb about 3/8 inch rearward as compared with the B4B.On our test engine, the compression represents what you’ll get from a stock ’71 to ’76 junkyard 455 or what is running in your Buick right now.The Speed-Pro L2353F pistons start life with 27.8cc dishes, then add another 3 to 4 cc for the custom valve notches, bringing the total to about 32 cc.With Buick cores starting to thin out, we figure you’d better get it right when you build one, not only to preserve the breed but also to live up to the Hemi-stomping heritage with some real street power.
That’s what this story is here for–to deliver the facts about what works and what doesn’t on a simple, budget-built 455.
In fact, when Editor Glad did finally score a junkyard 455 while planning for this latest Buick story, the block turned out to be damaged beyond repair.
Instead, the engine core we used came from the voice of the industry, Dave Mc Clelland, who keeps a few in stock to feed his original ’70 GS455 four-speed convertible.
Presumably, this is so the Performer will line up the carb with a factory GS hoodscoop.
The dyno also couldn’t see a difference between the Performer and the B4B, as they performed identically pull after pull, thereby blowing the old Buick bench race talk that the B4B is a better intake.
The headers are for a Skylark, feature 1 7/8-inch primaries and 3-inch collectors, and were run with 18-inch collector extensions.