V8-300

The V8-300 is the 300 hp rating of Mercury's 4.6-litre (279 CID) 64-degree DOHC V8, a 32-valve naturally aspirated petrol outboard with 92 × 86 mm bore and stroke. FourStroke, Verado, Pro XS and SeaPro 300 all use this powerhead. The FourStroke hangs on a Conventional MidSection; the Verado hangs on the Advanced MidSection with DTS and optional Joystick Piloting; the Pro XS is the tournament calibration; SeaPro is the commercial duty rating of the same 300 hp.

Mercury introduced the 4.6 L V8 on 18 May 2018, replacing the supercharged 2.6 L inline-6 Verado 250 and 300. The old L6 Verado 300 weighed 635 lb / 288 kg. The new V8 Verado is published at 600 lb / 272 kg (AMS); the FourStroke CMS is 527 lb / 239 kg and the Pro XS CMS 511 lb / 232 kg — same block, different midsection, so this row does not carry a single weight_kg.

Pro XS 300 is still 300 hp. The 450R and 500R are supercharged 4.6 L V8 racing engines and are not this motor. Do not alias V8-350: that name already belongs to Volvo Penta's petrol V8-350.