I looked up their 540 spec sheet and didn't really notice the cam to be that large. The exhaust dur. may be a bit much however the lift is extremely conservative. That's just my opinion though. Check out some of the cam choices on CP's site. (more duration yet) Larger CI engines can handle a little more duration. I also notice they are advertising it as a 600 HP PLUS. There numbers may be on the conservative side here and are at 5,800 RPM. Not bad. It all boils down to how much people want to spend. Did you personally have a bad ecperience? If you build a lot of engines and have a large customer base your bound to have some issues no matter how good you are or your reputation is. It's difficult to hold up to an A-1 service or company now a days with the internet being so available for people to voice there opinions. It's not all that often people are completely truthful. Plus many people expect the best of the best without having to pay for it. It's a competetive market with no question.

I'm not hear to stick up for ATK however I do give them credit for addressing the issue. You'll notice many reps won't involve themselves in threads/posts on forums due to the fact they always get bashed and seem to never be able to win regardless. Many shops have closed up due to tough times and to be honest they probably don't really care who's left behind, customers, employees etc. I'm glad to see their still going strong.

I'm pretty sure ATK could have a 540 / 650 PLUS engine to market but probably wouldn't sell near as many due to the cost and perhaps even reliability.


Just like a marriage gone bad - you never really know what goes on behind closed doors.

I run the kb silvolite domed hypers in a supercharged application. 2 seasons now. If you set the engine up properly they work very well and I wouldn't hesitate to use them at 10:1. My effective compression was 13.2:1 last run of the season and the hypers came home fine. The pistons in the all forged engine, not so good (twin engine boat). I do run alum heads which help, but the key is setting the quench tight.

Nope. Just saw someone have issues with one of those 540/600HP engines. Issues where from parts that where spec'd and non I/O boating knowledge of those involved at ATK.

Just be careful here and of course, many other places without doing your homework first. Homework also includes having a good understanding of what should be in your motor, unless you pay very top $$$ and deal with a very well known marine engine builder. Knowing still helps though.