Terminator Cobra-Swapped Marauder Project: How Mercury Should Have Built The Ultimate Panther

Swapping a Mustang Terminator Cobra V8 into a Mercury Marauder is task that took some time and problem solving, but the end result is well worth it.

Many Blue Oval fans undoubtedly remember the Mercury Marauder, which was something of an improbable creation from the automaker that took a mundane, cushy and large sedan, and transformed it into a sweet-looking performance-focused ride for the whole family. Built only in the 2003 and 2004 model years, the Mercury Marauder came equipped with the naturally-aspirated 32-valve 4.6-liter V8, which generated a good-for-the-time 302 horsepower and 318 pound-feet of torque.

While that was impressive more than two decades ago, these days, plenty of Marauder owners have added things like superchargers to their rides in an effort to coax a bit more power out of them. However, YouTuber Chris Sullivan had a very different idea a few months ago – why not stuff a supercharged version of the 4.6 from the legendary Mustang Terminator Cobra of the same era under the hood of his Mercury Marauder, an engine originally rated to produce 390 horsepower and 390 pound-feet of torque?

Starting Out

This process really got underway back in May, which is when Sullivan had essentially finished assembling his pony car-derived powerplant, just waiting to be stuffed inside the engineless Marauder sitting in his garage.

There are a few issues that he discovers along the way, including the fact that he may not be able to use the Marauder’s oil housing adaptor, but nothing too major. He notes that this powertrain can’t be installed from the bottom up, as it won’t fit in between the frame rails, so he plans on stabbing both the engine and transmission in at the same time, from the top down.

Installation Woes

With the new powerplant assembled and looking amazing, Sullivan prepares to install it into his Mercury Marauder, but runs into a bit of a snag, which is to be expected with jobs like this. The sedan’s oil adaptor won’t allow the Terminator-style alternator to work, so he may have to use the Cobra’s oil cooler. The exhaust system will likely need to go as well, though he had originally hoped to retain it.

Sullivan also runs into issues in terms of finding a flex plate that will work, and admits that he may need to buy a new converter, even though the one he has is in perfect shape. With the frame modified to accommodate the alternator, that’s really the only piece of the puzzle remaining before he can actually install the new powertrain at this point – along with figuring out all the wiring.

Ready to Fire

It was just a couple of weeks ago that Sullivan got those things sorted out, but he also wound up having to relocate the fuse box to make it all fit. Regardless, the Terminator powerplant is now in place, and looking pretty OEM, we must say. There are several things left on the checklist before our host can go for a rip in their Cobra-powered Mercury Marauder, however, such as installing the fan, cooling hoses, and a few other bits and pieces.

Much of that gets done without too much trouble, and at this point, Sullivan just needs to clean up the wiring and complete a few more tasks – install the new injectors, add some fluids, and complete a few final checks before he can fire it up.

Ready to Roll

By the time a few days goes by, most of that is complete – the cooling and electrical systems are finished, leaving just a few things such as adding other fluids and finishing up the exhaust system. Once that’s complete, the new engine actually fires right up, but there is a small oil leak – albeit from a cheap eBay filter relocation line – and the battery isn’t charging, while there’s seemingly air in the power steering system, to boot. The oil line just needs retightening, and once the wiring is sorted out, the battery issue is resolved as well.

With the scratch-built intercooler setup installed, the car surprisingly suddenly refuses to start – but after lots of searching, Sullivan figured out that was caused by an issue with the neutral safety switch that made the car think it wasn’t in that gear. Regardless, the Cobra-powered Mercury Marauder is then able to finally pull out of the garage for the first time in months. There are still a few things to do before this project is finished, but major part – getting it up and running – is officially complete.

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Brett Foote

Brett Foote has been covering the automotive industry for over five years and is a longtime contributor to Internet Brands’ Auto Group sites, including Chevrolet Forum, Rennlist, and Ford Truck Enthusiasts, among other popular sites.

He has been an automotive enthusiast since the day he came into this world and rode home from the hospital in a first-gen Mustang, and he's been wrenching on them nearly as long.

In addition to his expertise writing about cars, trucks, motorcycles, and every other type of automobile, Brett had spent several years running parts for local auto dealerships.

You can follow along with his builds and various automotive shenanigans on Instagram: @bfoote.