I ran a Ateco built 540 in a Four Winns Liberator 241. Heavier boat than your checkmate, took it easy on holeshots and wave jumping, and the bravo lasted a while with no issues. Im sure the drive would be happier with a 3 blade.

I spoke to Bill and he said the engine was built with steel heads, runs 87 octane and is just what they expected a torque monster. Should run forever and and run smooth.
Bill's personal boat has Ateco 540's that are 750 hp. More expensive and a little more finicky docking engines with big cams.

Just as i thought. 600+ ft lbs from 3000 and up, nice stump puller!

Thanks to all for the insight.
As a new "go fast"ll boater I am not sure what to expect.
I am completely happy with the answers I got here. I am betting
This will be a bullet proof stump puller.
My thanks again to Bill at Ateco

If you need any accessories, gauges or rigging for the boat let me know. I will give a you a great deal as you are an Ateco customer!!

His tq. and HP range will be dictated by the parts used, and what he asked of his builder. Those numbers from a 540 should make for a reliable and powerful package in his 25 foot Checkmate.

vig - I'm not familiar with a '90 Checkmate but would guess your prop shaft is pretty deep in relation to the bottom of the boat. If that's the case, I believe a 3 blade prop (Mirage) would be a better choice than a 4 blade (Bravo). 3 blade will have a little more slip and therefore be a little easier on your out drive. Plus I think you'd see more top end with a 3 blade. That's allot of tq/hp so baby the out drive.

I had 500 hp (ZZ502) in a 1995 23 foot Wellcraft Nova. Boat weighs about 4,000 pounds and the prop shaft is deep, 7 3/4 inches down. The best prop I found for it was a labbed 25 Mirage Plus (3 blade prop). With that prop RPMs were generally in the 5250 - 5400 range. Your Checkmate hull is likely more efficient than my Nova hull. That said, a Mirage 27P might be a good place to start. Or maybe a 27 bent/labbed to 26 inches.

With that tq/hp you could be in the mid 70's, maybe more. So play safe!!

Good luck and have fun

Several have suggested that the numbers are low. If you look in the classified section you will see that Ateco is advertising two different 540s. One has 550 HP and the other has 600. Bill will build you what ever you want. I was just there last weekend and ordered a 540 that he says will put out 600. It all depends on the cam, heads, intake, carb, compression ratio etc. You are taking a big step up from the 454 and will love the result. This engine should be very reliable. Enjoy.

you said it, hey merc made two 540s one with 500hp one with 575hp. those are nice # for running in the 5200rpm range.

if you call brett at bblades he has a prop program, you pay for a prop say a b1 26 run it and if its to small pay for shipping ex andget a 28 if the 28 feels good but lags a little you send it back with lab money, now you have a custom prop and it was a exta 50 for shipping. he may send 2 out at a time not sure. how deep is your prop shaft to the keel of the boat that makes a diff on wether to go to a rev4 4 blade or mirage 3 blade both for deep prop shafts. if its under 5 1/2''you should go 4 blade if its 6'' to 7 1/2 is the deepest I have seen a rev or mirage is better. and when you get up on plane drive in tabs down throttle to 2500 then 3000 you should slowly pop on plane trim out a little tabs up and should be able to hit it from 3800 to open. Iran mine with 600 to 650hp stock b1 drive for 8 to 10 years and once Iwas going 35mph I would nail it til 6000rpm. with a 26b1. call me 617 833 3327 I will tell you about trimming getting on plane more. like I said earllier its a nice motor with years to run not tearing it down after 250hours. art ps speeds will be propped at 5200 so figure 74 to 77 depending where your prop shaft height is you could always go to a imco 2'' shortie to pick up speed, thats what I did and hdy steering

As stated above...some motor builders knowingly overestimate their numbers. Some are built with different parts as well. Leon builds great motors.