Vig

Post some specs on the heads, cam, compression ratio etc and we can give you some accurate feedback, everything else now would be a"what if" and a WAGMAR ( Wild Ass Guess Made At Random) and would be useless for comparison purposes!

Best Regards,
Ray @ Raylar

I am sure this was Dynoed with my new CMI Wet exhaust and I know Bill also put in both new water pumps.

For the question below I bought this motor it is not a rebuilt.

As far as the cam and all I am looking for a really durable motor maybe that is why it is not reaching the additional horsepower.
This motor is going into my 25 Checkmate, Any guesses on what to expect speed wise?
Also any theory on how to attempt to begin to prop it?

If the engine was built with GM heads, thats very close to right on the money. I'm sure the cam is on the mild side for longevity. Sounds like a nice package.

Billl at Ateco builds what you want...properly.

Congratulations on your new engine! Ateco can make whatever horsepower you want. He knows how to make real horsepower not just happy dyno power some builders like to play with. If the customer wanted a 575 hp engine that is what you will get. Ateco has built 620 plus hp with Mercury 502's with heads, cam and EFI remaps. Seems to me you got a bullet proof setup. You better be careful if you have a Bravo drive with all the torque. That engine is going to pull like a freight train in that Checkmate.

This looks like a Leon Derebery motor...no offense...but his 540 motors put out almost as much as yours. You should be in the 625 to 650 HP range.

Well according to the latest post with specs it is advertised as 575 horsepower and it made 574.3.

I think you got what you paid for.

Enjoy that should be a nice setup.

When you want more just add a Whipple. My 540's with AFR 345CC heads and Whipple Stage II superchargers made 824 HP at 5500 RPM with 6-1/2 lbs of boost.

Bill at Ateco has been building motors a VERY long time. Dyno numbers make good conversation, but arent a end all for everything. Sure, you can make 700HP N/A on a 540CI. Its all in what the customer wants out of the motor, and what he wants to spend. A guy who wants to run 87 octane, and run stock iron GM heads, and a conservative valvtrain, will obviously make less than a guy who is willing to drop the $$$ for aftermarket heads, higher octane, big cams with dry exhaust, etc.

You should have a real reliable setup from Bill, and 575HP and 600+ft lbs arent nothing to turn your nose at! Enjoy

I have run Ateco engines in my own personal boat and have installed them in other boats and other performance applications and something just doesn't seem right with those numbers. I'm not sure you are reading the dyno sheets right. The 550 is a pretty reliable workhorse engine. Looking at the dyno sheet it shows that the peak torque of 643 ft. lbs. @ 4000 rpm and 574 hp @5300 rpm is a good reliable engine. The 550 is a good reliable engine. The 550 is not intended to be a race engine. What you have is a strong engine that can pull like a rino and the numbers are backing that up. Unless you are wanting to race your boat I think you will be pleased with your 550. Id say if you have any questions you should go to Bill.

A friend has a 25 checkmate with a 454 and a whipple, and it runs very well. I think you are going to very happy with the new built power plant. I think with all the torque you have, you may be able to spin a 28 Bravo1. Pretty sure that's what my friend runs. Take it easy out of the hole or you will be replacing the drive soon.

3 blade, let it rev/lower pitched prop, no hole shots, might save the drive for a while.