How-To: Coyote Swap in a 1999 Ford Mustang10/10/2019
Getting Ford Performance’s second-generation Coyote V-8 ready to drop into our 1999 Mustang seemed like cake when we started. Actually dropping the Coyote engine into the SN95 chassis still seemed easy when we updated you a month later. A few months after that, we knew things were not going to go as smooth as a typical LS swap when we reported hitting a brick wall with the fuel system and ECM wiring. Here’s what it took to finally get the car moving under its own power.
Sometimes things are just much more easily said than done. Usually, it’s those tasks where numerous details have to be stacked up and worked out one after the other before the objective can be achieve. You know, things like the D-day invasion, putting a man on the moon, and Santa Claus delivering handmade toys to all the girls and boys around the world in one night. And you can add to that putting a Coyote crate engine into our Fake Snake 1999 Mustang GT.
OK, so maybe we exaggerate a little, but not much. For this project, we’re leaning on the expertise of Pro Dyno in Fort Mill, South Carolina, who specialize in both race and hot street Mustangs. Lead technician Paul Connor had the old 4.6 two-valve modular out and the new Coyote crate engine mated to the transmission and back in the car in less than two days. The mechanicals went relatively smoothly, but Connor warned us that the work had hardly even begun. We should have listened.
Still to be done were the new fuel system, cooling system, plumbing for the power steering, and wiring. None of that posed a problem for Conner and the rest of the staff at Pro Dyno, but getting all those details right does take time. That’s why there has been a bit of a delay between updates with this project Mustang. Pro Dyno owner Dan Desio graciously offered his shop and crew to handle the Coyote swap, and he did his best to work us in whenever possible, but Pro Dyno stays incredibly busy with tons of cool cars coming through the shop, and sometimes the Mustang understandably had to take a back seat.
Still, we are finally there. Ford provides excellent instructions with both their Coyote crate engines and wiring harnesses. It makes dropping a modern Coyote crate into something like a Cobra kit car or an older carbureted vehicle—say a classic Mustang or an F-100 pickup—pretty straightforward. It gets a bit tougher when putting a modern, computerized engine into a modern, computerized car. We couldn’t totally rip out the old computer because we needed it to run non-engine systems for things as simple as the reverse lights, so we had to integrate the new engine computer to the existing computer. That’s where Conner at Pro Dyno was absolutely invaluable. To be honest, this isn’t exactly a “do it over a weekend in your driveway” kind of project. We’re building the car to be able to handle 750 or more horsepower with the eventual addition of a blower or turbos, and the upgraded fuel and cooling systems also added to the complexity. Having a resource like Pro Dyno helped avoid lots of potential mistakes that could have turned this project into a quagmire of frustration.
So now we’ve finally got the 430hp Coyote running in our 1999 Mustang GT and we’re confident it is properly fueled and cooled. Next up we’ll put a couple hundred miles on it for a proper break-in, then get it back on the dyno for some tuning to see how much it really makes. We’ve got a lot to cover here, so let’s get to it!
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