Re: What Cubic Inch 572, 622?
 

First, you can add a blower by yourself. No computor to recalibrate.
Second, if something happens to the fuel system I can most likely fix it in an hour and not take the boat to someones shop for two weeks.
Third, I'll put more money in my bank.

Re: What Cubic Inch 572, 622?
 

That's a motor! Thanks.

Re: What Cubic Inch 572, 622?
 

Who sells a high performance closed cooling system for my engine?

Re: What Cubic Inch 572, 622?
 

I was under the impression you could use a closed cooling system for a diesel engine... i think they have alot more capacity than the ones merc is using on there closed systems in the racing dept... I agree with you the engine packages i have been looking at look great with the efi setups.. but on twins i can save about 10k with carbs... i can deal with that...

Don

Re: What Cubic Inch 572, 622?
 

I understand that carbs can make more power. But a Pro stock engine isn't the same as a marine engine.They have to be tuned differently. The torque ranges are different if i'm correct. You would want your peak torque around 4700-5300 rpm in a boat,that is being used for pleasure. A drag boat which is totally different operating conditions. The engine for the Magnum Sport is great looking. The intake looks similar to mine. Heres a pic.

Re: What Cubic Inch 572, 622?
 

Fasterdamit,
I agree using carbs with blowers that are added later is much easier.The fuel injectors on my engines are GM injectors. If I need an injector I just go to get one they are not something special.

Re: What Cubic Inch 572, 622?
 

Re: What Cubic Inch 572, 622?
 

My plans are as you described. Single carb set up. Lookin towards a 598ci.

Re: What Cubic Inch 572, 622?
 

Tonto,

What RPM is your peak HP made on the 572? I run my 598" at 6500 RPM WOT and think dual quads may give me some gains up there. I cruise at 4000 - 5000.

Craig

Re: What Cubic Inch 572, 622?
 

Why not go with a Donovan aluminum block(or similar) 752ish cubes, and, closed cooling? Then, just change the cylinder sleeves at rebuild time. The additional upfront costs could be mitigated by later savings in machine work, shipping, etc.

Also, the aluminum engine blocks would save a few pounds, and are often repairable by welding.

Re: What Cubic Inch 572, 622?
 

I wonder what the price difference is.

Re: What Cubic Inch 572, 622?
 

I would be afraid of the bravos and the kind of toques 750ci would make. Also boats like rpm, how tight could you turn that combo in a boat for sustained periods of time. I think there is probably a reason no one else is using a motor that big. Just my $.02.

Re: What Cubic Inch 572, 622?
 

Re: What Cubic Inch 572, 622?
 

Thanks for the info Robert, this could come in handy!!

Re: What Cubic Inch 572, 622?
 

2 X 1050 DOMINATORS is a whole different sport than 2 X 775's. :p The 2X1050 set-up would probably really come alive at 7500 rpm, not likely to be seen in a boat though.....The "small bore" carbs preformed flawlessly on my set-up, super responsive everywhere in the rpm range. I propped for 62-6500.

A single is definately easier to deal with, but a properly matched tunnel ram and carb combo will make more tq and power than a single any day with the exception of the very bottom end. But with 600+" motors, trust me there is plently of tq down low...especially on bravos. :D :D

Re: What Cubic Inch 572, 622?
 

"Bigger is Better". One thing no one has brought up is the cost. Price out engines up to 598CI and then ask about bigger. Price of everything jumps up a lot after 598CI. Limiting factor will be the price.

Re: What Cubic Inch 572, 622?
 

I have heard that the rod stroke ratio is not right on the motors over 572. So that is something to think about.
Hunter

Re: What Cubic Inch 572, 622?
 

I have a 598 with a Hyd roller cam package 186 hours so far and no complaints or tinkering. Idles at 900... The only problem I had was finding a prop big enough to harness the power.

Re: What Cubic Inch 572, 622?
 

How much HP are you making??

Re: What Cubic Inch 572, 622?
 

Ya, and is that idle in gear or out?

Re: What Cubic Inch 572, 622?
 

Big motors are pretty easy to get to idle. They tend to produce a pretty good vacuum signal to the carbs even with large cams. Actually cam selection in many of these motors is limited to valvetrain durability, rather than over camming the motor. It is very easy to over cam a 454 or 502 with a cam that is still pretty mild as far as valvetrain durability. Particularily with hydraulic rollers the lifter limitations can make it very difficult to over cam 600+ motors. Solid rollers are another story!!

Re: What Cubic Inch 572, 622?
 

39NAS-T,
Rod to stroke ratio is definately something to consider. Many 572's use 6.5" rods which creates a little concern for an endurance motor, but there are still a lot of motors out there with that rod doing just fine. A better choice is a 6.7" or 6.8" rod with a 4.5" stroke for a rod to stroke ratio close to 454's and 502's.

Re: What Cubic Inch 572, 622?
 

I'm very happy with my Cobra 750's. They make 740 hp @ 600 ci, single Nickerson 1050. They idle at 750 rpm's and midrange will impress anyone!!! They run cold (120 for water and oil temp will not register on the guage). Boy are they loud with Stelling headers, so I'm trying GGB muffers. If you use Stelling be sure you don't block the stinger water exsit with a exhuast flapper.

I run Max Machine bravo's ... so far great!!!

Re: What Cubic Inch 572, 622?
 

I guess those MAX MACHINE bravo's are the chit!

Re: What Cubic Inch 572, 622?
 

What heads are proven best for 598ci natuaral asperated? Dart Pro1 C&C'ed seam to be very popular.

Re: What Cubic Inch 572, 622?
 

I think JC Perf hit the nail on the head. Dart 355, AFR 357, and Brodix will be very close in power generation and good choices for the money. More exotic heads like Big Chiefs can make more power for more $$$.