Ford Mustang 1967 Fastback 408 cui Stroker

Plenty of 1967 Mustang fastbacks that look bone-stock at a car show are hiding a very different engine underneath — a 351 Windsor stretched to 408 cubic inches with a stroker crankshaft. Built right, the combination can push past 400 horsepower at the rear wheels while still fitting in the same engine bay as the factory small-block. Here’s how builders turn a common Ford block into a genuine sleeper.

Beautiful Fastback!!

Under the skin of plenty of 1967 Mustang fastbacks that look bone stock at a cruise night, there’s a very different engine than Ford ever put there. Owners chasing more displacement without going full big-block have landed on a formula that starts with a common 351 Windsor block, bored slightly oversize, then stuffed with a stroker crankshaft to push total displacement to 408 cubic inches. The result looks almost identical to the small-block Ford originally built. It doesn’t behave anything like one. With the right heads and fuel system, that combination can push well past 400 horsepower at the rear wheels — from a motor that still fits where a stock 289 once lived.

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Building 408 Cubic Inches From a 351

The 408 stroker starts life as a 351 Windsor block, typically bored .030 inch over stock, then fitted with a forged 4340 steel stroker crankshaft and matching H-beam connecting rods to stretch displacement well beyond the factory 351. Forged pistons bring compression to around 9:1 — high enough to make real power, conservative enough to tolerate pump gas — while keeping the whole package built to survive sustained high-rpm use rather than just a single dyno pull. Builders typically also upgrade the oiling system and rebalance the rotating assembly during the swap, since a stroker crank places different stresses on the bottom end than the factory 351 ever saw.

Heads and Fuel Decide the Personality

Builders typically choose between aftermarket aluminum heads like Trick Flow’s Twisted Wedge 11R or AFR’s 185cc and 205cc castings, each tuned for a different rpm band — the smaller 185cc heads favor low-end torque, while the 205cc castings are built to breathe at higher engine speeds. Paired with either a traditional carburetor or a modern Holley EFI throttle body system, a well-matched 408 combination can deliver 400 to 425 horsepower at the rear wheels, with a broad torque curve that makes the car genuinely fun to drive on the street, not just impressive on paper.

A Stroker That Still Looks Stock

Part of the appeal is that a 408 build fits in the same engine bay as the original small-block, so a fastback carrying one can still look completely factory-correct at a glance — right up until the driver puts their foot down and the car pulls like nothing Ford sold in 1967. That sleeper quality is part of the draw for owners who’d rather surprise people at a stoplight than announce the build with a hood scoop and loud graphics.

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