Looking at re powering my Baja. Currently I have a 496 Mag producing 375 HP. I was set on finding a 500EFI or 525EFI but during my search I came across a carbureted 540 ci 8.9L from Mercruiser. New engine which produces 440 HP and 540 torque. The HP is clearly lower than the 500 or 525 but my understanding is the 540 opens up a lot of upgrade options down the road which won't require computer upgrades like with a EFI. 540 new is selling for $17,900. Any thoughts on the plus or minuses of going the 540 carbureted route versus a 500EFI or 525EFI?

Disclaimer: Technically challenged but slowly learning thanks to many on this site. Thanks to all who chime in.

Sounds interesting

Find yourself a good stock bore 502 8.2 and build a 540, you can do it cheaper than 18K and make way more power than 450.........unless you have no engine skills...

Edit: just read the disclaimer.........

BINGO...disclaimer. Little to no engine skills.

Power 440 HP (328 kW)
Full Throttle Range 4200-4600 RPM
Displacement 540 CID (8.9L)
Engine Type 8.9L Mercury V8 Iron Block & Remanufactured Heads
Bore & Stroke 4.50” X 4.25” (114 mm X 108 mm)
Compression Ratio 8.6:1 With Forged Pistons
Rocker Arm Ratio 1.7:1 Stamped Steel
Fuel Requirement 87 Octane (R+M)/2
Fuel System Holley 800 CFM Electric Choke Carburetor, Mechanical Fuel Pump
Induction System Single-Plane Aluminum Intake With Bronze Crossover & Pads
Ignition System Thunderbolt V with Knock Control
Charging System 65 Amp / 917 Watt Alternator
Water Drain System Multi-Point Drain – Hand Removeable Blue Drain Plugs
Exhaust System Iron Manifolds with 4” Dia. 316 SS Dry Joint Exhaust Elbows
Cooling System Thermostatically Controlled Raw Water – 143 F
Accessory Drive System Serpentine Belt
Lubrication System High Flow Oil Pump , Copper Oil Cooler, Oil Thermostat
Recommended Engine Oil SAE 25W50 FC-W Synthetic Blend Racing Oil
Audio Warning System Oil Pressure, Coolant Temperature, Drive Lube


Stamped steel rockers, 4600 rpm redline..... is that what you really want in your boat?

We installed one of these engines in a 22 donzi and were very pleased with the performance of it. I would have to say it is slightly under rated power wise. Comes with all the nice accessories and hardware. For the price it is hard to beat. Later down the road the power upgrade options are easy and endless.

Been looking at this motor my self, but here is a new 540 MPI with headers for 26.5K
Genuine Mercury & Mercruiser parts. Mercury Racing 540 EFI

Looks like a nice package!

Limited skills, I'd say to look at this. Plenty of hp right off the bat, lots of torque, and much less $.

502 HO Big Block Crate Engine | Chevrolet Performance

I think the carbed 540 is a nice upgrade from what you have now power wise. You can run this motor for a season or two as is and be happy. When more power is desired a cam swap, head work and new valvetrain can be done by a reputable performance marine shop for less than 5K. That should bump the HP north of 600 and you'll be grinning every time you fire the motor. Buy the carbed 540!