800 HP Dodge Charger 605 cid / 9.9 L

A naturally aspirated 605 cubic inch Mopar big block making 800 horsepower sounds like it belongs under a modern turbocharged hood, not a classic Dodge Charger. Stroking a factory B/RB big block to this size takes it well past anything Chrysler engineers built at the factory, and it puts this Charger in the company of other 605-inch Mopar builds chasing the same big-inch, no-boost philosophy.

Eight hundred horsepower usually comes with a turbocharger whining under the hood or a supercharger poking through it — but this Dodge Charger builder skipped the boost entirely and went the old-fashioned way instead. Nine-point-nine liters of naturally aspirated Mopar big-block sit under that hood, a displacement number so large it sounds like a typo next to the factory 440s and 426 Hemis this car’s ancestors carried. Getting there means machining a stock big-block block and crank combination far past anything Chrysler engineers ever intended, and it raises an obvious question for anyone who has priced out a turbo kit: is stroking a big block to absurd proportions actually the smarter way to find 800 horsepower?

Turning a Factory Big Block Into a 605

Mopar’s B and RB big-block family — the engines that powered the 383, 400, 413, 426, and 440 — were never factory-cast anywhere near 605 cubic inches. Builders get there through a stroker combination: a longer-throw crankshaft, larger bore, and a set of connecting rods matched to push the displacement well past what any factory big block ever offered. It is the same approach Mopar engine shops use to push 383s and 440s up to the 600-900 horsepower range without touching a turbo or blower, just taken to one of its more extreme conclusions.

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The Company This Charger Keeps

This isn’t the only 605-cubic-inch Mopar build making the rounds among enthusiasts. A Pro Touring-style 1973 Dodge Charger SE has been built around a custom 605 cubic inch big block rated at roughly 805 horsepower and 740 lb-ft of torque, and forum builders on Mopar big-block boards have documented their own 605-inch street Hemi projects targeting 750 to 800 horsepower on pump gas. The displacement number shows up often enough in the Mopar world that it has become something of a benchmark for big-inch, big-block builds without forced induction.

Why Some Builders Still Skip the Boost

Turbos and superchargers are the fastest route to four-digit horsepower today, but a big-inch stroker offers something boost can’t fake: a torque curve that feels like it never stops pulling, without any lag or heat-soak to manage. For a street-driven Charger, that tradeoff — more built-in displacement instead of more plumbing — still has plenty of believers, even as some Mopar shops now bolt twin turbos onto similarly sized big blocks for numbers well beyond 800 horsepower.

The B and RB Family’s Original Design Intent

Chrysler’s B and RB big-block engines were designed in the late 1950s and early 1960s to power full-size family sedans and station wagons as much as performance cars, a mainstream engineering assignment that gave the basic architecture generous material in the block castings and a genuinely robust bottom end from the start. That built-in overbuilt quality, originally intended simply to survive decades of ordinary family use, is exactly what modern stroker builders exploit when they push the same castings to displacements and power levels Chrysler’s engineers never targeted.

Why Stroking Beats Boring for Big Displacement Gains

Builders chasing serious displacement gains generally favor stroking, which increases the crankshaft’s throw to lengthen piston travel, over simple overboring, which only enlarges the cylinder diameter and has real practical limits before the cylinder walls get dangerously thin. A stroker combination lets a builder add meaningful cubic inches while keeping the block’s structural integrity intact, which is exactly the approach behind pushing a factory big block toward the 600-cubic-inch range without resorting to an aftermarket block casting.

Naturally Aspirated Torque Has a Character Boost Can’t Replicate

Drivers who’ve spent time behind both naturally aspirated big-inch strokers and comparable boosted engines consistently describe a difference in how the power arrives, a big stroker tends to deliver a smooth, continuous pull across the rev range, while boosted engines can feel like the power switches on once the turbo or supercharger reaches full boil. For a street-driven car meant to be enjoyed in everyday traffic rather than just at wide-open throttle on a drag strip, that predictable, linear torque curve is a real selling point that keeps naturally aspirated big-block builds relevant even in an era when forced induction dominates the horsepower charts.

The Charger’s Long History as a Big-Block Canvas

The Dodge Charger nameplate has served as a big-block canvas since its 1966 introduction, when it debuted with Chrysler’s 426 Hemi as an available option alongside smaller B-series engines, and that association between the Charger name and serious displacement has followed the nameplate through every generation since. A modern big-inch Charger build like this one is less a departure from that heritage than a continuation of it, simply pursuing the same “biggest engine that fits” philosophy with modern machining tolerances and decades of additional engine-building knowledge behind it.

Where the Stroker Community Draws the Line

Even within the Mopar big-block community, there’s a practical ceiling most builders respect: push displacement and compression too far without matching upgrades to the rotating assembly, cooling system, and fuel delivery, and reliability suffers fast. The builders who successfully campaign big-inch street cars tend to be the ones who treat every supporting system as part of the build, not just the block and crank, which is exactly the kind of comprehensive approach that separates a genuinely reliable high-horsepower street Charger from a fragile show-only trailer queen.

Machining Tolerances That Didn’t Exist in the 1960s

Modern CNC machining and precision balancing equipment let today’s engine builders hold tolerances that simply weren’t achievable on a mass production line in the 1960s and 1970s, which is part of why stroker builds pushing well past factory displacement limits can still be genuinely reliable street engines rather than fragile, short-lived race pieces. That gap in available machining precision between the era these blocks were designed in and the tools builders use to modify them today is a big part of what makes projects like this 605-cubic-inch Charger possible at all.

Fuel and Ignition Systems Have to Scale Up Too

Pushing a big block toward 800 horsepower means the fuel delivery and ignition systems supporting it have to scale up right alongside the bottom end, since a stock-sized carburetor or fuel pump sized for a factory 440 simply can’t feed an engine producing nearly double the airflow demand. Builders chasing these kinds of numbers typically upgrade fuel pumps, fuel lines, and ignition components as a complete package alongside the stroker assembly itself, treating the whole combination as a single engineering problem rather than a series of isolated upgrades.

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