Can You Really Put GM LS Heads on a Ford Small Block?
Bottom line: You can bolt LS heads onto a Ford small‑block, but you’ll need custom adapters, a revised intake, and realistic expectations about power and reliability.
Can You Really Put GM LS Heads on a Ford Small Block? – Pros, Cons & Compatibility
Image: Can You Really Put GM LS Heads on a Ford Small Block? – Pros, Cons & Compatibility – Performance Comparison and Specifications
Design & Looks
The LS family uses a 90‑mm bore spacing and a five‑bolt pattern on the head. Ford’s small‑block (1932‑2001) has a 4‑bolt pattern and a different bolt‑hole circle. That mismatch means you can’t just swap the heads – you need a fabricated adapter plate or a custom head bolt set. The LS heads also sit lower in the deck, so you may have to adjust the block deck height or use a short‑deck block to keep the compression ratio in check.
Visually, LS heads give a modern, angular look compared to the classic wedge shape of a Ford head. If you’re after a street‑rod aesthetic, the contrast can be appealing, but it also adds complexity to the engine bay layout.
Performance & Mileage
LS heads are famous for large valves and excellent airflow, which can boost a Ford small‑block’s horsepower by 30‑50 HP when paired with a matching LS intake manifold and camshaft. However, the gain isn’t free. The change in combustion chamber shape often forces a lower compression ratio, so you may need higher‑octane fuel to stay efficient.
- Improved top‑end flow – better breathing at high RPM.
- Potential loss of low‑end torque if cam and intake aren’t tuned.
- Fuel economy may stay similar; the swap is about power, not mileage.
Price & Rivals
Doing the swap yourself can run $2,000‑$3,500 for adapters, custom gaskets, and a compatible intake. Buying a ready‑to‑install LS‑swap kit pushes the cost to $4,000‑$6,000. Compare that to a brand‑new LS engine (often $4,000‑$7,000) or a modern small‑block crate engine, which may be cheaper and fit without custom parts.
For most hobbyists, the LS‑head swap is a fun engineering challenge rather than the most cost‑effective power upgrade. If you already own a small‑block and want to experiment, the price can be justified; otherwise, a full LS swap or a high‑performance aftermarket small‑block may make more sense.
| Engine | Mileage (mpg) | Price (USD) | Top Features |
|---|---|---|---|
| Ford Small‑Block (original) | 15‑20 | $1,200‑$2,000 | Classic design, wide parts availability, easy to work on |
| GM LS (stock) | 12‑16 | $4,000‑$7,000 | Large displacement, robust aftermarket, high power potential |
| Ford Small‑Block + LS Heads | ~15 | $2,500‑$6,000 (swap) | Improved airflow, modern look, DIY challenge |
FAQ
- Can I use stock LS pistons with a Ford block? No. The piston‑to‑deck height differs, so you need LS‑compatible pistons or a short‑deck block.
- Will the swap affect my car’s emissions? Yes. Changing the head geometry usually requires a custom ECU tune to stay legal.
- Is the LS‑head swap worth it for street driving? It’s worth it if you enjoy hands‑on building and want a modest power bump. For pure performance, a full LS engine or a modern aftermarket small‑block is usually more efficient.
If you’ve tried this swap or have questions, drop a comment below – I love hearing about real‑world experiences.
Source: Read Official News
