E3 spark plugs were used throughout...
E3 spark plugs were used throughout the testing.
Our engine uses a bone-stock oiling system, though we found that even the low-volume oil pump gear needed to be shaved 0.010 inch to avoid an interference problem with the oil pump cover.
All our testing was done using an internally balanced flywheel borrowed from Bruce Kent, a Meziere electric water pump, Rockett Brand 91-octane gas, an MSD ignition, E3 spark plugs, and a set of Hooker headers coated by Jet-Hot. The headers are for a Skylark, feature 1 7/8-inch primaries and 3-inch collectors, and were run with 18-inch collector extensions. We used a Holley 750-cfm Street HP carb for every test, and it was determined through testing that 32 degrees of total timing made the most power.
Stare long and hard at this...
Stare long and hard at this shot of the Edelbrock B4B (left) and Performer intakes and you won't see a whole lot of difference other than the carb-pad location. The dyno found none.
Small Cam, Dual-Plane Intakes
Our first round of dyno tests used the TA Performance hydraulic flat-tappet cam known as the TA-212. It specs out at a tame 218/230 degrees of duration at 0.050 tappet lift. The lobe-separation angle is 112 degrees, and valve lift is 0.459/0.470 inch using stock replacement shaft-style rocker arms (Sealed Power PN R857) with a 1.55:1 ratio.
Using what is perhaps the smallest cam seen in CC this decade, we ran four intakes across the 455: an Edelbrock Performer, an Edelbrock B4B, a TA Performance SP1, and a TA Performance SPX. 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. 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. Both cranked some numbers we were happy with, though: 426 hp at 5,300 rpm and 513 lb-ft at 3,500 rpm with more than 500 lb-ft from 3,100 to 4,100. With a near-stock idle quality, this setup proved to be the one we loved the most with the stock heads.
Our Holley 750 Street HP carb...
Our Holley 750 Street HP carb is fitted with a pair of Adjust-A-Jet blocks from Percy's High Performance. These eliminate the jets and make fuel-curve tuning super simple with just a turn with a screwdriver.
Small Cam, Single-Plane Intakes
Next we moved on to the single-plane intakes, trying the smaller TA Performance SP1 and the larger, taller, more hard-core SPX that features a water passage under the plenum that can be used to cool the intake; we did not take advantage of that feature during dyno testing. Intuitively, both single-planes were out of place with the tiny camshaft, but true to our forecast, they made more peak power while giving up lots of bottom end. The pivot point in the curve was at 4,300 to 4,500 rpm; below that point, the dual-planes made more power, and above that point, the single-planes were superior. Looking at peak numbers only, the SPX intake produced 443 hp at 5,500 rpm and 500 lb-ft at 3,600 rpm. As usual, if you consider the average power throughout the entire curve, the dual-plane and single-plane look very similar because they just trade high-end and low-end power, so the overall average does not change much: In this case, the average numbers from 2,100 to 6,000 rpm only differ by 1 lb-ft and 2 hp. However, look at the power when plotted on a graph in this story and then consider the rpm range where you'd really drive a tame combo like this and you'll opt for a dual-plane with the small cam. It's a shame no one makes a high-rise dual-plane for the Buick.
As for comparing the SP1 with the SPX, it seemed the gnarlier SPX was better by a few numbers at the very low end and at the top end. Oddly enough, both single-planes made virtually the same power between 3,500 and 4,500 rpm. Averaging the power from 2,000 through 6,000 rpm, the SPX was superior to the SP1 by just 3 hp and 4 lb-ft.