The centerpiece of the iconic 1991 GMC Syclone is, without a doubt, the turbocharged 4.3L V6 LB4 engine. This power-dense six-cylinder produced a very respectable 280 horsepower and 350 pound-feet of torque, enabling the compact pickup to out drag a Ferrari 348TS in a famous test that was published in the September 1991 edition of Car and Driver.
While the LB4 V6 engine is certainly impressive, it’s not a performance powerhouse by modern-day standards. Aftermarket parts company Holley caught up with a 1991 GMC Syclone owner at its LS Fest East event, Chris Germano, who decided to lift the LB4 V6 out in favor of something a bit more powerful: a turbocharged 427 LS V8.
This custom Syclone features a block manufactured by the Michigan-based engine experts over at Dart Machinery Inc., which was topped off with CNC machined LS3 heads, a Brian Tooley Racing camshaft and an 88 mm turbocharger. Power is sent to an upgraded four-wheel-drive system through a modified GM 4L80E four-speed automatic transmission. Germano did not say how much power his Syclone is putting out, but with a turbocharged 7.0L V8 sitting under the hood, we get the feeling he’s not hurting for more performance. Rounding out the mods are some QA1 suspension parts, aftermarket black-painted alloy wheels and a set of Mickey Thompson Street S/S semi-slicks.
Our favorite part about this build is that Germano stayed true to the Syclone’s character, retaining much of the factory interior and applying minimal exterior modifications, as well. This build could also be used for daily errands, as it retains the factory seats, an air conditioning system and a stereo.
Check out the video embedded below to learn a bit more about Germano’s unique LS-swapped 1991 GMC Syclone and to see it in action on the drag strip.