You can - with a lot of work and effort. A better bet would be Toyota's TRD ( Toyota Racing Development) Supercharger kit for the FJ. If you have installed at a Toyota Dealer, they will even warranty it. The FJ's 4.0 V6 is about 205 rear wheel horsepower, with the supercharger you'll get about 260 hp ( 300 at the flywheel) - a very noticeable increase. So you'll still get decent gas mileage, have more horsepower, and will have factory reliability. All this comes at a price - about $3,800 for the kit and another $400- $500 for the install - but it makes the FJ a blast to drive! Hope that helps, Dean
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