Announcement from Mercury Racing and the American Power Boat Association (APBA)
Goodbye to the 450R and Hello! to the 500R as the official factory stock class.
Jeff Broman, director of Mercury Racing, said they have been discussing this for over a year now, “I think everyone is excited about stepping up to Mercury Racing 500R outboards for 2025.” Every racer wants more power, and here is another 50 HP delivering an additional 10% torque over the 450R, weighing 720 lbs.
The 500R comes with a 4.6 litre engine, a 64-degree DOHC V8 powerhead, and a monster Mercury exclusive supercharger! with Mercury’s exclusive components and features that optimizes performance, including the R-Drive and the R-Drive Sport Gear Cases.
It’s a new benchmark for outboard power density with the upgraded 500R engine cooling system design that allows the ECM to optimize performance under any condition, including humidity compensation technology—producing a gain of up to 30mph.
The 500R outboards prepared by Mercury Racing for Factory Stock competition will feature the following changes from regular production specifications:
- A revised ECU calibration permits higher peak RPM for broader propping options, and a less-aggressive Engine Guardian program.
- Standard engine mounts are replaced with heavy-duty mounts for enhanced stability and durability under the most extreme conditions.
- The cooling system is modified to be compatible with high transom mounting positions by removing the idle relief muffler, which permits higher exhaust temperature.
- For competition, the 500R outboard will be offered two gearcase options. Racers may choose the production R-Drive Sport 5.9-inch surfacing gearcase with a 1.5-inch diameter propshaft. Teams with a significant investment in racing propellers for the 450R outboard may select the race-proven Speed Master gearcase with a 1.25-inch diameter propshaft and continue to use those propellers. Mercury Racing will offer a full range of five-blade CNC Cleaver propellers for both the R-Drive Sport and Sport master gearcase.
“The transition to 500R power should be seamless,” said Broman. “Teams should not have to make significant changes to boat rigging or weight distribution. The consumer versions of these boats are already running the 500R production outboard, and the builders have the set-up dialed in. We expect that Factory Stock boats powered by the 500R outboard will see up to a 5 mph gain in potential top speed compared to 450R outboard power.”
The Factory Stock 500 class is designed to foster close competition and features 35-foot to 40-foot catamaran boats equipped with full safety canopies, including models produced by Marine Technologies Incorporated (MTI), Doug Wright Powerboats and Skater Powerboats. Each is powered by twin Mercury Racing 500R outboards. All boats must be out of a production mold as certified by Offshore Powerboats Association (OPA) Racing. No custom-built boats are permitted and the outboard engines are stock and factory sealed. The Factory Stock class competes on a closed course that is typically five miles in length with multiple turns. The boats are capable of a top speed exceeding 130 mph on flat water but are usually propped shorter for improved acceleration.
They are all on a level playing field, so let’s see what happens in 2025.
Visit www.mercuryracing.com for more information.
