Building a 625 Horsepower Coyote Street Engine That Turns 8,500 rpm

This Coyote V8 build takes an unusual path to big power: first converted to carburetors, then switched back to fuel injection using an AEM Infinity standalone ECU and Ford Racing parts, ultimately reaching 625 horsepower and spinning to 8,500 rpm without any forced induction. Produced by Power Automedia’s EngineLabs team, the build has sparked a comment section full of swap ideas, from a 1970s Road Runner to a Fox-body Mustang. Watch the full build to see how a stock Coyote gets there.

Ford built the Coyote V8 from day one as a fuel-injected engine, tuned by a factory computer smart enough to manage direct combustion, cam timing, and fuel delivery down to the millisecond. So naturally, one shop’s first move was to rip all of that out and bolt on carburetors instead. What sounds like a step backward turns out to be the setup for something else entirely: a return trip to fuel injection, but this time on their own terms, chasing a number that sounds almost implausible for a naturally aspirated small-block — 625 horsepower, spinning to 8,500 rpm without a turbo or supercharger in sight.

Why Carburete a Fuel-Injected Engine at All

Converting a Coyote to carburetion sounds counterintuitive on a modern engine, but it’s a well-worn strategy for builders who want maximum flexibility during the development phase of a project — carburetors are simpler to swap, tune on a dyno in real time, and troubleshoot without a laptop, which makes them a practical starting point before committing to a specific fuel injection setup. This build used that carbureted phase as a baseline before making the deliberate move back to EFI with modern hardware. It also let the team isolate mechanical issues — valvetrain behavior, oiling under high rpm, bottom-end durability — before adding the additional variable of a standalone computer’s fuel and ignition maps, a methodical approach that’s common in serious dyno-development work but often skipped by hobbyist builders working on a tighter budget and timeline.

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AEM Infinity Takes Over

The heart of the return-to-injection conversion is AEM Electronics’ Infinity standalone ECU, a fully programmable engine management system that gives tuners far more granular control over fuel and ignition timing than the Coyote’s stock factory computer ever offered, especially once the engine is pushed well outside its original factory parameters. Pairing that level of control with Ford Racing hardware let the team extract meaningful gains that a bolt-on carburetor setup simply couldn’t match.

8,500 RPM From a Production-Based Small-Block

The Coyote’s factory redline sits meaningfully lower than 8,500 rpm in stock form, which makes the build’s ability to safely spin that high a genuine engineering accomplishment rather than a marketing number. Reaching that kind of rpm ceiling on a production-based architecture typically requires reinforced valvetrain components, upgraded rotating assembly parts, and precise fuel and ignition control at every point in the rev range — exactly the combination this EFI conversion was built to deliver. Builders chasing this kind of rpm ceiling typically upgrade valve springs, retainers, and rocker arms first, since factory components are simply not designed with that kind of sustained high-rpm operation in mind, and a single valvetrain failure at 8,500 rpm can destroy an engine in a fraction of a second.

625 Horsepower, Naturally Aspirated

Without forced induction, reaching 625 horsepower from a Coyote-based small-block represents serious specific output for a five-liter engine, achieved through the combination of high-rpm capability, precise EFI tuning, and supporting hardware rather than brute displacement or boost. That figure puts this build well ahead of most naturally aspirated factory Coyote variants, without the added heat, complexity, and packaging demands a supercharger or turbo system would introduce to the engine bay. For comparison, even Ford Performance’s own naturally aspirated Coyote lineup tops out at 580 horsepower with the 5.2L Aluminator XS — the most powerful N/A modular crate engine Ford has ever built — which means this build’s 625-horsepower figure still edges past the best Ford itself offers off the shelf, territory usually reserved for boosted applications.

The Power Automedia Network Behind It

This build comes from Power Automedia’s stable of enthusiast publications, a media network built around dedicated titles for nearly every performance niche — StangTV for Mustangs, LSXTV for GM performance, Dragzine for drag racing, and EngineLabs for exactly this kind of deep technical engine build content. That specialization is part of why the build documentation goes well beyond a simple dyno number, linking out to a full technical writeup of the conversion process for readers who want to replicate it.

An Engine Bay Without Borders

The comment section turns the Coyote’s versatility into a running joke and a genuine engineering discussion at once, with viewers proposing the engine in everything from a 1970s Plymouth Road Runner to a Fox-body Mustang notchback to, only half-seriously, a Mazda Miata. That enthusiasm reflects the Coyote’s growing reputation as one of the most swap-friendly modern V8s available, thanks to strong aftermarket support and a wide range of standalone ECU options like the one featured in this build. Whether any of those swaps ever actually happen, the willingness of viewers to picture the engine in cars from three completely different decades and price brackets says a lot about how far the Coyote’s reputation has traveled beyond its original home under a Mustang’s hood.

Carrying On a Family Connection

Among the more practical comments is one from a viewer building a 1992 Fox-body Mustang that belonged to his brother, who passed away eleven years earlier, specifically because he wants to install a Coyote like the one shown here. It’s a reminder that engine swap content like this doesn’t just serve as a technical reference — for some viewers, it’s a direct roadmap for finishing a deeply personal project. That kind of comment doesn’t get a technical reply from the channel, just an acknowledgment, but it’s the sort of thing that sticks with a build long after the horsepower numbers have been forgotten by everyone except the people directly chasing them.

How Far the Platform Has Come

Commenters also note that later-generation Coyotes, benefiting from factory refinements Ford made across the engine’s production run, are now reportedly making 510 to 520 rear-wheel horsepower on relatively modest bolt-on packages combined with E85 fuel, without anything close to the level of standalone tuning documented in this build. That progression says something important about how far the platform has come since its debut — what once required a full aftermarket ECU conversion to achieve is edging closer to something a well-chosen parts list and a tune can deliver on its own. It also hints at where the Coyote platform is headed next: as factory internals and aftermarket support keep improving in tandem, the ceiling for what counts as an extreme naturally aspirated build keeps climbing right along with it.

Check out the full video above and let us know what you think in the comments.

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