Free Parts Cost - Performance Q&A

Kevin McClelland Mar 1, 2010 0 Comment(s)

Lacking A Few Liters
Q: I have an '08 Impala with a 3900 V-6. I have been told the police package with the same engine has 300-plus horsepower. Is it possible to get this power out of my engine with some simple modifications, such as a chip? Thank you.

Jim Hershberger
Via email

A: The police-package Impala is equipped with a 5.3L V-8 LS-based engine. This engine produces 303 hp and 323 lb-ft of torque. This little runner is a wolf in sheep's clothing. The Impala SS also has this engine combination and is a very fun car to drive. Knocking down over 25 mpg on the highway and an easy low 15 seconds in the quarter-mile, it's a nice four-door family cruiser. The only thing you need is nice strong arms to hang on to the steering wheel when you stand on the throttle-torque steer can be rather entertaining.

Your 3.9L base engine comes with 233 hp and 240 lb-ft of torque. Very few aftermarket companies offer hop-up components for your powertrain. You can add a K&N air filter PN 33-2334, and MagnaFlow offers an after-cat exhaust system PN 16708 to free up a couple extra ponies. As for performance reprogramming, JET Performance offers a Stage 1 and 2 Power Control Module for your Impala, claiming a gain of up to 25 hp, and it's 50-state legal. Check with JET for more information on these. With these components you'll see a nice bump in your power curve over stock. If that's not enough, trader her in for a V-8.

Boy, I've Done It Again!
Q: I'm sure you started a firestorm of controversy about not calling the Gen III/IV "small-blocks." Hopefully, I can help set the record straight.

It definitely was GM's intention to have the Gen III perceived as the next generation of small-block evolution. The catchphrase at the time was: "Maintain the essence of the original SB but do what has to be done to prepare it for the 21st century!" Maintaining the 4.400-inch bore spacing fell into the "essence" category, even though we argued for more. We did manage to sell the bank-to-bank offset change, however, by eliminating the old offset con rods and the left/right piston/rod assemblies.

Your point about the Gen III resembling a Ford Modular was purely coincidental. Our benchmarking group was called the Mona Lisa Project and they did not have a Ford Modular to compare with at that time. I did try to arrange a tour of the Ford Romeo Engine Plant so my team could benchmark their product and processes, but they wouldn't let us in. In the early '90s the Modular was top-secret stuff!

The Gen III was initiated because we felt any further improvements in the Gen I, the Gen Ia, and the Gen II SBs were like picking fly specks out of the pepper. The changes were very expensive and the incremental gains were hard to measure.

It's only a matter of time until the old-style SBs become GM's equivalent of the Ford Flathead.

Don Webb
GM Powertrain
Gen III/IV Design Manager, ret.

A: Many thanks for a very informative letter giving us a view back to the formative years of the LS-based engine family. As we've stated before, the LS-based powerplants are world-class, and we love to make big power with them. We sure wish you guys would have won the battle on the bore spacing. Just think what we could do with, let's say, a 4.600-inch bore spacing!

Yes, the incremental gains that the Gen I/Gen II engine family gave was extremely hard to come by with the emissions requirements and the power bogeys set by the upper management. The Gen III reset the clock on power potential and specific power output.

We're now 23 years since the Gen I was put to bed and 12 years past the Gen II's bedtime. The Ford Flathead was done in passenger car use in the early '50s. The way we see it, we have another 30 years to go before the Gen I makes it to the ranks of the Flattie! Yes, its time will come, and we can't wait to see what "pushrod" small-block The General will have us playing with in the year 2040!


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