Fourth-Gen LS Engine Swap - Finance-Friendly 408, Part 4

Our homegrown iron-block mill finally finds its way under the hood of a project car

Chris Werner Jul 1, 2011 0 Comment(s)
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Am I getting lazy in my old age? Perhaps. Even if I were, it doesn’t explain why an engine swap that began last summer took eight months to complete. Other, more tangible reasons factored in, like being in graduate school 500 miles away. And, as mentioned in the brief project update last issue, I screwed up the clutch installation and rendered my Trans Am non-shiftable, which accounted for a large part of the holdup. More on all that in the photo captions.

Ghtp 1107 01 Fourth Gen LS Engine 2/26

This story is intended to show the general details of an engine swap, and points out a few of the more critical things that are good to know when installing an iron block and/or Gen IV intake in an F-body. A refresher on our engine’s specs: LQ4/LQ9 iron block, K1 Technologies forged crank and rods, forged Wiseco pistons, GMPP CNC-ported L92 heads, 11.0:1 compression, 408 cubes. You’ll find more specs in the photo captions, but see the first three installments of the story series in the August 2009, September 2009, and August 2010 issues for the nitty-gritty details; all three are also available on gmhightechperformance.com. And be sure to check out the conclusion section below for info on our friends at Tune Time along with final thoughts on the project.

Conclusion
In the end, Matt Hauffe of Tune Time Performance did a number on the tune. It exhibits great driveability and we have no complaints whatsoever (except the speedo is off a tad, no biggie and a quick fix). I expected significant “surging” at low speeds with a camshaft this large, but happily it is kept to a bare minimum. While the car idles great and sounds downright nasty doing so, Matt made it clear that this cam (251/267 at 0.050, .624/.624-inch lift, 115 LSA) is a poor match for our unported L76 intake manifold, which starts gasping in the midrange and is completely out of breath by 6,300 rpm. Swapping to a smaller, torquier grind and/or replacing the manifold with an aftermarket piece compatible with the tight F-body cowl are options for the future.

However, a further boost in power is not exactly a necessity, because my TA is now the first car I’ve owned that actually scares me. Yeah, I’ve had rides that put more power to the tires, but never anything that came close to these numbers naturally aspirated. There’s something about the raw nature of an N/A mill that’s pretty darn intimidating—and with no turbo to quiet the exhaust or supercharger to muffle the intake snarl, the sound is truly awe-inspiring. Mission accomplished.

Sources

SPEC Clutch
Bessemer, AL 35022
800-828-4379
http://www.specclutch.com
Tune Time Performance
Lakewood, NJ 08701
732-349-7800
www.tunetimeperformance.com
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