For UK builders working on classic Fords, kit cars, Cobras and lightweight specials, the Ford small block crate engines remain one of the most rational families available. It is compact, familiar, well supported and capable of everything from a calm fast-road character to serious circuit and drag performance.

Within that family, three displacements appear again and again: 302, 347 and 363. On paper they look like simple steps in cubic inches. In practice, they behave quite differently, and the right choice depends far more on vehicle mass, usage and driveline than on headline power figures.

This guide takes a detailed look at 302 vs 347 vs 363 specifically for UK builds, with an emphasis on real vehicles, realistic roads and realistic budgets. The objective is not to repeat catalogue claims, but to frame each engine as a tool for a particular type of project, then help you decide which tool you actually need.

The Small Block Ford Platform in Context

All three engines share the same core small block Ford architecture. Physically, that means broadly similar external dimensions, familiar mounting patterns and a huge ecosystem of supporting parts. That is one of the reasons they work so well in UK projects:

• Compact enough for Escort, Capri, kit car and Cobra style shells

• Easy to service once installed

• Extensive choice of manifolds, sumps, ignition systems and ancillary parts

• Predictable behaviour when correctly specified

Displacement changes are achieved through variations in bore and stroke. As stroke increases, the engine’s character tends to shift towards stronger torque at lower RPM, with potential trade offs in rev ceiling and long term stress if the package is pushed hard without appropriate supporting parts. Bore changes influence breathing, chamber shape and piston design.

In other words, 302, 347 and 363 are not three versions of the same engine with different numbers stamped on the side. They are three different answers to the same question: how much torque and power does this vehicle genuinely need, and over what RPM range.

302: The Baseline Small Block

The 302 is the traditional starting point for many UK small block builds. It is compact, well understood and offers enough performance to make a light car very fast without becoming difficult to live with.

In a typical classic Ford shell, Cobra replica or Seven style chassis, a well built 302 provides a balance of power and manners that suits fast-road driving, touring and occasional track work. It is usually easier to keep civilised than a larger displacement variant, particularly on wet roads and in short wheelbase cars.

From a builder’s perspective, the 302 has several practical advantages:

• Parts availability is excellent and pricing is generally favourable

• Many off-the-shelf fitment solutions assume a 302 footprint

• The engine can be specified conservatively yet still outperform the chassis it is going into

In road biased cars, the 302 is often the point where additional power begins to deliver diminishing returns unless the rest of the vehicle is significantly upgraded. It will still respond to cam, intake and exhaust improvements, but it rarely forces the builder into the more serious driveline and chassis work that a larger engine can demand.

For UK drivers who want a classic small block character, usable performance and the option to enjoy the car on B roads without constantly managing wheelspin or noise, the 302 remains a rational and often under appreciated choice.

347: The Stroker That Bridges Road and Serious Performance

The 347 stroker exists because in many cases the 302 feels like a starting point rather than a final answer. By increasing stroke and displacement, a 347 delivers more torque across the range and greater overall output for a similar external package.

In practice, that means:

• Noticeably stronger midrange than a comparable 302

• More relaxed overtaking and higher gear flexibility

• Greater potential when paired with suitable heads, cam and induction

In UK builds, the 347 often becomes the engine of choice where the car is expected to do more than occasional fast-road work. A well specified 347 can support regular track days, spirited touring and aggressive driving without losing too much civility, provided the calibration and gearing are chosen sensibly.

The trade off is that a 347 will reveal weaknesses elsewhere sooner. Clutches, gearboxes, propshafts and differentials that live happily behind a mild 302 may start to complain when a 347 is used as intended. Brakes and tyres also move from “nice to improve” to “essential to upgrade” more quickly.

For many UK projects, the 347 is the point where the engine begins to feel truly modern in its torque delivery while still retaining the compact, familiar small block format. It is the engine that often makes sense when a car needs to feel noticeably more capable than a period spec build, without crossing into the more extreme behaviour of larger units.

363: Maximum Displacement Within the Small Block Envelope

The 363 is usually the largest sensible step within the classic small block footprint. It is a stroker that pushes displacement to a level where the engine becomes something quite different from a traditional 302 road motor.

A 363, specified properly with appropriate heads, cam and induction, will typically deliver:

• Very strong torque from low engine speeds

• High overall output potential for circuit, drag or serious track builds

• A more urgent, assertive character that demands respect on the road

In the UK, this sort of package is most at home in cars that are either track focused, drag focused or built as high value restomods with significant chassis and driveline work behind them. It is not inherently unsuitable for road use, but the rest of the vehicle must be ready for what it delivers.

A 363 will usually highlight any marginal component choices. Gearboxes, props, differentials, mountings and even bodyshell stiffness all become more critical. Tyre selection, suspension geometry and brake specification have to be taken seriously if the car is to remain enjoyable, not simply quick in a straight line.

For builders who want a small block Ford that behaves like a serious performance engine rather than a traditional fast-road unit, the 363 provides a very strong foundation. The question is rarely “can it make enough power” and more often “how much of that power can the chassis genuinely use in UK conditions”.

Character and Use Case: How They Feel Rather Than What They Dyno

Dyno numbers are useful, but they do not explain how a car behaves in traffic, in the wet, or on a narrow B road. From a driver’s seat perspective, the three engines tend to present themselves as follows when correctly put together.

A 302 in a light shell typically feels eager but manageable. It rewards revs without absolutely requiring them, and gives enough performance to be interesting without dominating the car. Drivers can explore the chassis without feeling as though the engine is constantly trying to escape.

A 347 adds a sense of effortlessness. Throttle openings that felt normal on a 302 now deliver more acceleration with less apparent strain. The car pulls harder from lower revs and spends more of its time in what feels like a sweet spot. It is often the most satisfying balance for mixed road and track use.

A 363 tends to make the engine the defining feature of the car. On the right road or track it is deeply impressive. In marginal conditions it can easily overwhelm older chassis, modest tyres or conservative suspension setups. For some drivers that is part of the appeal. For others it simply means they rarely get to use more than a fraction of what is available.

Framed that way, the decision between 302 vs 347 vs 363 becomes less about maximum numbers and more about how and where the car will be driven.

Fitment, Cooling and Ancillary Systems

Because all three share the small block footprint, basic fitment is broadly similar. Engine mounts, header options and bellhousing patterns often carry across with minimal modification. However, the supporting systems around the engine should scale with displacement and intended use.

Cooling is a good example. A mild 302 with sensible calibration will usually be content with a well specified aluminium radiator and an appropriate fan package. A 347 used regularly on track or a 363 making serious power will need more headroom. Radiator core size, shrouding, fan capacity and coolant routing become more critical as heat output rises, especially in compact classic bays.

Oil control is another area that benefits from forward planning. Deep sumps, baffling and, in some cases, additional capacity are more than just “race extras” in stroker builds. They can be the difference between a long lived engine and one that suffers from oil starvation during hard cornering or braking.

Exhaust systems also interact with displacement. A mild 302 will tolerate relatively simple systems. Higher output 347 and 363 builds respond better to carefully sized primaries, collectors and overall system design, not only in terms of peak numbers but in drivability and tractability.

Driveline, Gearing and Chassis Implications

It is impossible to choose between 302, 347 and 363 in isolation from the rest of the drivetrain.

Behind a 302, many established gearbox and differential combinations will survive comfortably if the car is driven as a fast-road or occasional track machine. With a 347, it becomes sensible to confirm that clutch capacity, gearbox rating and differential strength are aligned with realistic torque levels. With a 363, it is usually a case of designing the driveline to suit the engine rather than expecting existing components to cope.

Gearing choices also shift with displacement. A 302 may enjoy shorter overall gearing that allows it to sit further up the rev range in normal use. A 347 can often pull slightly longer gearing without feeling lethargic. A 363 may benefit from longer gears to exploit its torque and prevent the car feeling “busy” at realistic road speeds, especially on motorways.

Chassis work follows the same pattern. Brakes, tyres, suspension geometry and shell stiffness all become more important as the engine becomes more assertive. A 302 can often be installed into a well maintained classic with only moderate upgrades. A 347 usually asks for more serious attention. A 363 expects the surrounding car to be built to a corresponding standard.

Choosing Objectively: Matching Engine to Project

An objective way to choose between 302 vs 347 vs 363 is to treat the engine as a response to clearly defined constraints rather than a starting point.

Ask, for example:

• What is the realistic finished weight of the car with fluids, driver and fuel

• How will it actually be used in the UK, not just how it is imagined on paper

• What level of torque can the chosen gearbox and differential support

• How much of the displacement will be usable on typical roads and in typical conditions

• What is the long term plan for track days, touring or competition

For many classic fast-road builds, a well specified 302 is sufficient and may even be more enjoyable. For mixed road and serious track use, a 347 often provides the ideal balance of torque and civility. For heavily developed cars with suitable driveline and chassis work, or for specific drag and circuit applications, a 363 can be entirely appropriate.

Where Billy’s Fits Into the Decision

The reality of these choices is that they are easier to make with access to engines, parts and people who understand what happens once the car leaves the workshop.

Billy’s supplies Ford small block crate engines in 302, 347 and 363 configurations, along with cooling packages, sumps, ignition systems, fuelling components and driveline parts that match each displacement and intended use. For builders who are still deciding whether a small block is the correct platform at all, the broader Ford Performance engines overview provides context on how these engines sit alongside Coyote, EcoBoost and Godzilla options.

By treating the 302, 347 and 363 not as abstract catalogue entries but as distinct answers to specific project requirements, it becomes far easier to select an engine that will feel right in the finished car, behave predictably on UK roads and stand up to the sort of use the vehicle is actually going to see.