2020 RXP-X 300 Rear Exhaust — Transition Bulletin

GT40 Marine | Doc GT40-SD-EXH-RXP-2020-BULLETIN | Single-Year Hull Transition Note | Rev 1.0 — 2026-05-24

TL;DR

The 2020 RXP-X 300 is a transition-year hull. It is NEITHER fully 2016-2019 NOR fully 2021+. Use this bulletin to choose the correct kit before ordering.

What changed in 2020

BRP revised the RXP-X 300 hull mid-cycle in 2020. The internal exhaust routing geometry shifted, but the external through-hull approach angle stayed similar to 2016-2019. This created a single-year hull that doesn't perfectly fit either the 2016-2019 kit OR the 2021+ kit.

| Year | Internal J-pipe routing | External through-hull approach | Compatible Kit |

|---|---|---|---|

| 2016-2017 | Original geometry | Standard | GT40-SD-EXH-RXPX300-1619 |

| 2018-2019 | Original geometry | Standard | GT40-SD-EXH-RXPX300-1619 |

| 2020 | Transition geometry (revised internal, standard external) | Standard | See below |

| 2021+ | New geometry (off-axis routing) | Tight 2021+ approach | GT40-SD-EXH-RXP-2021P |

| 2024+ 325HP | Different platform entirely | Different platform | Use ST3 family — NOT this RXP family |

2020 RXP-X 300 install path

For 2020 hulls specifically, install the GT40-SD-EXH-RXPX300-1619 kit with the following modifications:

1. The 2016-2019 V-band clamp at the J-pipe-to-manifold joint is the correct part for 2020. Use it.
2. The 2016-2019 stainless outlet flange has a slight angular offset that does NOT match 2020 internal routing. When installing the outlet:

• Pre-fit the outlet against the J-pipe delete adapter exit
• You will notice a 4-6 degree rotational misalignment
• Loosen the J-pipe delete adapter from the manifold by 1/2 turn on the M10 SHCS
• Rotate the J-pipe delete adapter by the required offset to bring the outlet into alignment
• Re-torque all 6 M10 SHCS to 42 Nm (31 ft-lb)

1. Cooling water injection — the 2020 hull uses the 2016-2019 cooling water reintroduction routing. Follow the 2016-2019 kit's Step 6 instructions verbatim.
2. 2020-specific note on the inner side panel — 2020 hulls have an additional T20 Torx screw on the port-side inner panel that 2016-2019 hulls don't have. Do not lose it during removal — it is a smaller fastener than the rest.

What to do if the misalignment exceeds 10 degrees

A small subset of 2020 RXP-X 300 hulls were built later in the year using interim 2021+ geometry. If the outlet misalignment exceeds 10 degrees after the rotational correction in Step 2:

1. Do not force the install. Forced alignment causes outlet stress fractures within 50 hours of operation.
2. Stop, photograph the misalignment, and email support@gt40marine.com with hull HIN and the photographs. GT40 will identify whether your specific hull is the early-2020 or late-2020 variant and ship the correct outlet flange replacement at no charge.

Why this is a bulletin and not a standalone guide

The 2020 RXP-X 300 is a single-model-year hull with limited production. A full standalone guide would duplicate ~90% of the 2016-2019 kit guide content. This bulletin captures the 10% that differs, keeps install documentation maintainable, and points the installer to the correct base guide.

Connects to

• GT40-SD-EXH-RXPX300-1619_EXHAUST_INSTALL_GUIDE.md — full install procedure
• GT40-SD-EXH-RXP-2021P_REAR_EXHAUST_INSTALL_GUIDE.md — 2021+ kit (NOT compatible with 2020)

Support

• Email: support@gt40marine.com
• Site: gt40marine.com
• Install help on 2020 hulls specifically: include the hull HIN, model year confirmation, and photographs of the misalignment if applicable

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This bulletin is © 2026 GT40 Marine. All rights reserved.