Tom Wilson
November 1, 2010

Which brings up injectors-are they properly sized for the crate motor you're installing? You need new engine mounts unless you already have aftermarket mounts. We recommend urethane mounts as they hardly affect vibration but are vastly more durable than rubber. Don't forget to change the transmission mount, too.

Moving beyond the engine compartment, consider the clutch, transmission, and driveshaft, dealing with each as necessary. Unless you just installed a new clutch, plan on a new one with the new engine. Transmissions are typically OK and most Mustang transmissions are easy enough to change on their own, so they need not be changed automatically along with the engine.

Driveshafts are forever, but U-joints aren't. Replace them as necessary is the fiscally responsible advice; we swapped in an FRPP aluminum driveshaft to easily gain new U-joints and lose a few pounds.

And what about the rest of the car? Are the tires good? Do you need a brake upgrade to match your new power? The cost must be factored into the budget and the parts acquired before grabbing the wrenches.

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Making the Swap
We don't have the room here to detail an engine change step-by-step, but in general, it's best to unhook the original engine enough to lift it out of the car, then strip it as necessary while it's out on the ground. At the same time, the new crate engine can be dressed with as much as you can get away with-headers are a joy to install out of the car-then put into the car.

Remove the vulnerable radiator before the engine, and you'll find pulling the transmission makes handling the engine that much easier. You might want to support the rear of the engine with a floor jack or stand once the transmission is out, especially if the engine mounts are shot.

Obviously you need some large tools, such as an engine hoist. A transmission jack and muffler stand (if you're lucky enough to work on a hoist) are nice, but not absolutely necessary. A suitable concrete floor is a must, and it's best to plan on having the car down for a week, typically because last-minute parts are required. A helper or two are mandatory in spots as well. For these reasons, most folks opt for pro installation, but if you have the tools, go for it.

Air conditioning turned out to be the least of our installation worries. By unbolting the compressor from the engine and laying it over a fender, it was possible to swap engines without breaking into the air conditioning system. That means no trip to an AC shop to have the system discharged and refilled later. You have to work around the bulky AC hoses and compressor, but it's still the best option.

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Because we wanted functioning EGR, we wanted to use the stock threaded fittings at rear of each head. These came blocked with steel fittings on the X302, and sealed with red Loctite. They wouldn't unscrew, so Ricardo drilled them to form an air passage. Greasing the drill bit and fishing for leftover chips with a magnet got the job done. As there is no gasket at this head-to-EGR-pipe connection, Ricardo used copper ultra-high-temp RTV silicone as a gasket.

If you have stock rubber heater hoses sticking out of the firewall, carefully remove them. Slitting them lengthwise first is smart as the heater-core nipples have a tendency to rot and pull out now that Fox heater cores are 20 years old. This begs the smart decision to replace the heater core-a hateful under-dash job you just might have to put off for a few more paychecks. If so, and your Fox already has silicone hoses, just leave 'em. The hoses might be slightly stained, but they can be safely reused, thus avoiding a wrestling match with a weakened heater core.

Finally, consider what to do with your old engine. Most people are happy enough to donate the old hulk to the install shop. Also, a used T-5 transmission that isn't beat to death is trade-worthy, so you might inquire if your core parts have any value to the shop.

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