# United States tariff lines under HS 8409.91

> The United States tariff splits HS 8409.91 (other: Suitable for use solely or principally with spark-ignition internal combustion piston engines) into 11 national lines: 8409.91.10.40 (for vehicles of subheading 8701.21, 8701.22, 8701.23, 8701.24 or 8701.29, or heading 8702, 8703 or 8704), 8409.91.10.60 (for marine propulsion engines), 8409.91.10.80 (other), 8409.91.30.00 (aluminum cylinder heads) and 7 others.

Source: https://border.bot/countries/united-states/hs-codes/840991
Last updated: 9 October 2026

[Countries](https://border.bot/countries) / [United States](https://border.bot/countries/united-states) / [Chapter 84](https://border.bot/countries/united-states/hs-codes/84) / [8409.91](https://border.bot/countries/united-states/hs-codes/840991)

## Key facts

- HS subheading: [8409.91](https://border.bot/hs-codes/840991)
- National lines: 11
- Tariff: [United States](https://border.bot/countries/united-states)
- Chapter: 84: Nuclear reactors, boilers, machinery and mechanical appliances; parts thereof

## United States lines under 8409.91

The United States tariff splits HS 8409.91 (other: Suitable for use solely or principally with spark-ignition internal combustion piston engines) into 11 national lines: 8409.91.10.40 (for vehicles of subheading 8701.21, 8701.22, 8701.23, 8701.24 or 8701.29, or heading 8702, 8703 or 8704), 8409.91.10.60 (for marine propulsion engines), 8409.91.10.80 (other), 8409.91.30.00 (aluminum cylinder heads) and 7 others.

- [8409.91.10.40](https://border.bot/countries/united-states/hs-codes/8409911040) Other, Suitable for use solely or principally with spark-ignition internal combustion piston engines (including rotary engines), Cast-iron parts, not advanced beyond cleaning, and machined only for the removal of fins, gates, sprues and risers or to permit location in finishing machinery, For vehicles of subheading 8701.21, 8701.22, 8701.23, 8701.24 or 8701.29, or heading 8702, 8703 or 8704. Duty (MFN): free
- [8409.91.10.60](https://border.bot/countries/united-states/hs-codes/8409911060) Other, Suitable for use solely or principally with spark-ignition internal combustion piston engines (including rotary engines), Cast-iron parts, not advanced beyond cleaning, and machined only for the removal of fins, gates, sprues and risers or to permit location in finishing machinery, For marine propulsion engines. Duty (MFN): free
- [8409.91.10.80](https://border.bot/countries/united-states/hs-codes/8409911080) Other, Suitable for use solely or principally with spark-ignition internal combustion piston engines (including rotary engines), Cast-iron parts, not advanced beyond cleaning, and machined only for the removal of fins, gates, sprues and risers or to permit location in finishing machinery, Other. Duty (MFN): free
- [8409.91.30.00](https://border.bot/countries/united-states/hs-codes/8409913000) Other, Suitable for use solely or principally with spark-ignition internal combustion piston engines (including rotary engines), Other, To be installed in vehicles of subheading 8701.21, 8701.22, 8701.23, 8701.24 or 8701.29, or heading 8702, 8703 or 8704, Aluminum cylinder heads. Duty (MFN): 2.5%
- [8409.91.50.10](https://border.bot/countries/united-states/hs-codes/8409915010) Other, Suitable for use solely or principally with spark-ignition internal combustion piston engines (including rotary engines), Other, To be installed in vehicles of subheading 8701.21, 8701.22, 8701.23, 8701.24 or 8701.29, or heading 8702, 8703 or 8704, Other, Connecting rods. Duty (MFN): 2.5%
- [8409.91.50.81](https://border.bot/countries/united-states/hs-codes/8409915081) Other, Suitable for use solely or principally with spark-ignition internal combustion piston engines (including rotary engines), Other, To be installed in vehicles of subheading 8701.21, 8701.22, 8701.23, 8701.24 or 8701.29, or heading 8702, 8703 or 8704, Other, Steel forgings. Duty (MFN): 2.5%
- [8409.91.50.85](https://border.bot/countries/united-states/hs-codes/8409915085) Other, Suitable for use solely or principally with spark-ignition internal combustion piston engines (including rotary engines), Other, To be installed in vehicles of subheading 8701.21, 8701.22, 8701.23, 8701.24 or 8701.29, or heading 8702, 8703 or 8704, Other, Other. Duty (MFN): 2.5%
- [8409.91.92.10](https://border.bot/countries/united-states/hs-codes/8409919210) Other, Suitable for use solely or principally with spark-ignition internal combustion piston engines (including rotary engines), Other, For marine propulsion engines, Connecting rods. Duty (MFN): 2.5%
- [8409.91.92.90](https://border.bot/countries/united-states/hs-codes/8409919290) Other, Suitable for use solely or principally with spark-ignition internal combustion piston engines (including rotary engines), Other, For marine propulsion engines, Other. Duty (MFN): 2.5%
- [8409.91.99.10](https://border.bot/countries/united-states/hs-codes/8409919910) Other, Suitable for use solely or principally with spark-ignition internal combustion piston engines (including rotary engines), Other, Other, Connecting rods. Duty (MFN): 2.5%
- [8409.91.99.90](https://border.bot/countries/united-states/hs-codes/8409919990) Other, Suitable for use solely or principally with spark-ignition internal combustion piston engines (including rotary engines), Other, Other, Other. Duty (MFN): 2.5%

## In other countries

No other national tariff on border.bot has live lines under 8409.91 yet.

- [The Harmonized System text for 8409.91](https://border.bot/hs-codes/840991)

- Previous subheading: [8409.10](https://border.bot/countries/united-states/hs-codes/840910) Parts suitable for use solely or principally with the engines of heading 8407 or 8408
- Next subheading: [8409.99](https://border.bot/countries/united-states/hs-codes/840999) Other

## Frequently asked questions

### How many national tariff lines does the United States tariff have under HS 8409.91?

The United States tariff splits HS 8409.91 (other: Suitable for use solely or principally with spark-ignition internal combustion piston engines) into 11 national lines: 8409.91.10.40 (for vehicles of subheading 8701.21, 8701.22, 8701.23, 8701.24 or 8701.29, or heading 8702, 8703 or 8704), 8409.91.10.60 (for marine propulsion engines), 8409.91.10.80 (other), 8409.91.30.00 (aluminum cylinder heads) and 7 others.

## Sources and updates

The tariff lines for the United States come from border.bot release 1 (edition 2026HTSRev21), read from the publisher’s files, and have been live since 9 October 2026.

The duty rates for the United States come from border.bot release 1 (edition 2026HTSRev21), read from the publisher’s files, and have been live since 9 October 2026.

The trade programmes for the United States come from border.bot release 1 (edition 2026HTSRev21), read from the publisher’s files, and have been live since 9 October 2026.

This page was last updated on 9 October 2026.

Guidance from published tariff data, not a binding ruling. For a decision customs must follow, apply to the destination’s customs authority for a binding tariff ruling.

Official source files:

- https://hts.usitc.gov/reststop/exportList?from=0000000000&to=9999999999&format=CSV&styles=false

Machine-readable: https://border.bot/countries/united-states/hs-codes/840991.json