When HPP introduced this engine project to our readers, neither Jim Taylor Engine Service (JTES) nor our staff knew if all of the pains would be worth the results. To recap, customer Bill Wise wanted to upgrade his JTES-built 0.035-over 455 to dip into the 11s after having run a best of 12.54 over the last few years. The challenge was to accomplish this feat knowing it would have to be done in Bill's 4,400-pound race-weight LeMans, while retaining its street manners.
JTES certainly left no stone unturned, with extreme attention paid to the new intake manifold, further porting of the existing 6X heads, and camshaft timing changes, along with the normal high-performance-engine-building acumen. Trying to shave more than a half-second in elapsed time given the restrictions is a major undertaking. What makes this story more exciting is that we have the rare opportunity to follow this buildup from inception to the dyno and back into the car for strip testing.
The custom-built 455 was transported...
The custom-built 455 was transported to the dyno facility at Bitner Automotive in Trenton, New Jersey. Jim Taylor (right) and Mark Erney carefully removed the powerplant from the back of the pickup truck and mounted it on the dyno cart.
In theory, the engine should produce nearly 500 hp on pump gas. But the dyno cell has often proven the math to be wrong, not only with Pontiac engines, but also with every internal combustion design. The water brake is the real deal, and all the bench-racing talk falls silent when the computer printer spits out the data, like it or not.
Preparation before you leave home is the key to a successful dyno session. Since this engine was run on the JTES test stand, we wouldn't be greeted with a surprise once the dyno loaded the crankshaft. You don't want to find out what's mechanically wrong, if anything, when it's on the dyno. The session is meant to get power numbers on the engine, not repair it.
The Pontiac ran like a champ on Bitner Automotive's dyno and never missed a beat. Idle was smooth, the vacuum signal strong, and the exhaust spoke with authority. The session was remarkably uneventful, which is a testament to JTES.
Did we reach our goal in the dyno cell and on the dragstrip? Well, you'll have to read the rest of the story to find out, but once again a Pontiac did not disappoint.
Once in the dyno cell, Mark...
Once in the dyno cell, Mark Bitner (right) and Mark Erney connected all of the components necessary to run the Pontiac engine and test it. As is common, the headers were mounted backwards to clear the water brake and connect to the dyno mufflers.
For the preliminary testing,...
For the preliminary testing, a Jim Taylor-built Holley 850 Double Pumper was employed. The customer had used a Demon carburetor, but since its calibration was unknown, the first runs were made with the tuned Holley.
It's important to check and...
It's important to check and confirm the proper operation of the throttle linkage from the dyno controls. You want to make sure WOT is reached, but it's even more important that the linkage closes quickly in order to not damage the engine after the pull is made and the load comes off.