To many truck enthusiasts, one of GMs biggest mistakes was not outfitting the S-10 and Sonoma line of compact pickup trucks with a V-8 engine. The idea is not new, and few aftermarket companies have been successful in installing a small-block Chevy into earlier models of these pickup trucks. However, with current emissions regulations and new smog laws, the idea seemed unfeasible. Yet we consulted with Steve Cole from The Turbo Shop in Compton California, who is an expert at GM computer programming and has a vast knowledge of emission testing procedures, to see if it was possible with current technology.

To begin, Cole set out to work with the Pontiac/GMC performance division and the plans for the truck were set. Pontiac/GMC sent Cole a '99 Sonoma extended cab, outfitted with a 4.3L V-6 and four-speed automatic transmission. They also sent a well-abused Pontiac Firebird that was used for testing at the Arizona Proving Grounds. Cole had the task of first removing the engine and transmission from the Sonoma, and swapping them out for the components from the Firebird. These included the LS-1 V-8 engine and the computer and ignition system, along with the 4L60E automatic trans- mission. Although the LS-1 didn't have too many test miles on it, Cole freshened up the LS-1 with a performance- grind camshaft from Competition I Cams and a set of Lingenfelter CNC- I ported cylinder heads. The result was 430 hp that would light the rear tires like a smoke bomb.

The installation, however, was not i so easy. The problems Cole faced in fitting the LS-1 into the Sonoma were I not out of the ordinary for earlier model swaps of this nature. Modifications to the truck's K-member had to be made because the LS-1 oil pan sump was too large. The pan was swapped out for a truck 5.3L oil pan, pump, and pickup, and some modifications to the transmission cross member were also made to fit the 4L60E out of the Fire- bird. Cole also used the front drive accessories out of a Corvette, as the alternator, power steering, and other items are more compact and tuck closer to the engine. This made it easier to fit the LS-1 into the small engine compartment of the Sonoma. Cole also had to fabricate an air intake duct, modifying the factory intake from a Chevy 6.0L Silverado and outfitting it with a K&N air filter.

The exhaust system also had to be fabricated. Cole made up a set of headers that exit into a free-flowing exhaust system and out through a large exhaust tip. But according to Cole, the hardest part of the installation was completely rewiring the engine harness to match the LS-1 computer to the Sonoma's instrument cluster.

Once the truck was completed, we were anxious to see what it was capable of. The combination of 430 hp and a lightweight truck prompted Cole to slightly detune the engine so that it would not sit on the launch pad and spin the tires all day long. Even so, we took the truck to Los Angeles County Race- way and managed to run a corrected time of 12.34 at 113 mph. The rear wheels spun a bit off the line but also broke loose in second gear, almost sending Cole into the guardrail on a couple of passes! We also had the opportunity to test the truck on a 200-foot skid- pad, where the Chassis Tech and Nitto tire combination actually showed some impressive cornering abilities-averaging 0.85 g's during our test.

Although the Sonoma doesn't look or sound menacing, driving it around town is like driving an old 427 SC Cobra or 427 '69 Corvette. The only exception is that the idle characteristics of the engine and its fine-tuning make the truck actually drive somewhat like a stock Sonoma-until you hammer on the throttle and get pushed back into your seat. On more than one occasion, we surprised the hell out of unsuspecting Mustangs, Camaros, Corvettes, and Porsches. Perhaps what best describes this truck is that it is a true "sleeper"-a shark of the street.

Despite some of the traction problems, Cole mentioned that he built the same LS-1 engine combination into a Pontiac Firebird, which then ran in the high 11-second range. Considering the Sonoma has a factory 3.08-geared rearend, more gearing and a traction device may make this truck even quicker. The potential is there and Cole is ready to move forward with the Sonoma to get it there.

In an upcoming issue, we'll hook up with Cole again and show how the engine was shoehorned into this truck, and if it is feasible for the average truck enthusiast to duplicate it. Furthermore, we will be working with Cole to upgrade the truck's brakes, rear end, interior, and other components as this project progresses. So the next time a pewter- colored Sonoma pulls up to you at a stoplight, make sure it doesn't have a TTS decal across the windshield. Otherwise, it might send you home with your tail between your legs.



The LS-1 V-8 was shoehorned into the Sonoma's engine compartment. This engine, however, is outfitted with a Competition Cams performance cam and a set of ported Lingenfelter heads. The combination with special computer tuning by Steve Cole makes 430 hp.

The Sonoma also received some Street Scene treatments, including a speed grille mounted in place of the factory piece.

The Sonoma can corner well too, averaging 0.85 g on a 200-foot skidpad. The combination of Chassis Tech dropped spindles, lower rear leaf springs, and Nitto tires really made a difference in its cornering performance. Imagine what it would do with a set of performance coil springs, shocks, and antisway bars!


The rear of the Sonoma was treated to the Street Scene Step Savers, giving the truck a smoother appearance. A Gaylord's tonneau cover was also painted the factory pewter to match the rest of the truck.



 

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