Sometimes you see something so ingenious, you wonder why it hasn't already been done. I felt that way when a friend a link to engine swap. It's brilliant. I reached out to the van's builder, Kevin Piper, to learn more about it.
"I'm not sure why anybody hasn't done it," Piper told me over the phone. "I mean, a few people have talked about the concept. I actually dreamt about doing that for years, and finally I got the okay from the wife, and I just kinda dove into it. I just didn't really know what to expect."
The key to this madness is GM's 4T65-E automatic transmission, which the company used in a number of front-wheel drive cars from the late 1990s to the late 2000s. That's what went in all of the GMT201 vans—including the Montana SV6. Crucially, the 2006-2009 Impala SS, one of few GM products to use Chevy's transverse, front-drive 5.3-liter LS4 V8, used that transmission too.
The 4T65-E was beefed up for the Impala SS, but it's the same basic unit that's in the Montana SV6. This meant that if Piper could manage to get the LS4 into the Montana, he wouldn't have to swap in a new transmission. He fabricated a new engine mount tying the engine to the subframe, and modified the passenger-side frame rail a bit so the engine accessories would have adequate clearance.
"Believe it or not, the hardest mechanical part for this build was actually the windshield wiper system," Piper said. "I had no room under the hood. I had to modify and kind of relocate it, and the windshield washer bottle is actually sitting in the trunk inside one of the panels."
The tough part was getting all the electronics to work. Piper estimates that he spent around 300 to 400 hours making the engine and vehicle communicate. Now, everything works, including traction control, ABS, cruise control and the car's anti-theft system. The only electronic item that doesn't work, Piper says, is the volume control on the steering wheel.
The vast majority of the items on this vehicle came from the GM parts bin. "Obviously nobody builds performance parts for minivans, " Piper noted. The transmission was upgraded, and a limited-slip differential was fitted to help mitigate what Piper described as "absolutely suicidal" torque steer with an open diff.
At the drag strip, the "Montana SS" runs a 15-second quarter-mile at 90 mph, which Piper notes isn't far off the factory-claimed 14.5-second quarter-mile for the Impala SS. And yes, it does burnouts. The fuel economy's not bad either, since the LS4 was one of the first GM engines to offer Displacement on Demand, running on four cylinders at light loads.
So why is Piper selling it? He told me he really just listed it to see if there was any interest in this sort of thing. If the right offer comes through, he'll sell, and build another one. Otherwise, he seems happy to hold onto it—he's already put over 10,000 kilometers on the conversion, including road trips all over Canada with his family. Does a V8-powered front-drive minivan sound like your kind of crazy? .