604ci or 572 ci
 

Is a 604 ci at 5300 rpm better than a 572 ci at 6000 rpm?

Re: 604ci or 572 ci
 

tourqe is what turns the prop go with the 604 no substitute for cubic inches

Re: 604ci or 572 ci
 

The only substitute for cu ins is MORE CU INS!!!
604 at 6500 now you talking

Re: 604ci or 572 ci
 

653 Supper Tall Decks are better yet, ZUL.

Re: 604ci or 572 ci
 

Depends on how you make the cubes...
I would go with the 572ci at 4.5/4.5 more rpm, less load on the drivetrain.

Re: 604ci or 572 ci
 

I agree, why not 598 at a conservative 56-5800rpms.

Re: 604ci or 572 ci
 

Joey Griffin want's to go 572 ci at 6000 rpm for 750 hp. I already have 604 at 5300 for 725 hp, but we blew a rod and now I'm afraid for the other engine. I talked to Joey and he does'nt like big ci cause of the long stroke. To hard on the rods.

Re: 604ci or 572 ci
 

I ran Oliver 6.7" rods in 632" with no problems, proped to turn 6200 NA and 6700 on the juice. Bottom end was good for 8200 according to the builder.

Re: 604ci or 572 ci
 

Whats the ratinal in going 604, why not go 598CI set up at 5400 very conservative rpms. I have had 4 of these, 2 on a 2000 Sonic with over 400 hours now, and the last 2 on my 4300 Nortech which has 140 trouble free hours. To many rpms for me, but I am somewhat conservative. 745 hp/763tq

Re: 604ci or 572 ci
 

http://www.offshoreonly.com/forums/s...hlight=TMP+750
Hopefully this will help. Its one combination that has worked great for me.

Re: 604ci or 572 ci
 

Thanks Jassman, I don't know much about engines, I'm learning as we go. I guess everybody has there own receipe. It's just that we have to find some engine builder that we'll have faith in. I'm talking with Joey Griffin, and I guess that he must be good since Reggie Fountain puts some of his engines in his boats.

Re: 604ci or 572 ci
 

NyKamp..
do you know what crank Zul put in those motors?? Bore and stroke and what rod length?? I am thinking of going big, but not sure if it will work NA. Mine comes out to 650" with 4 7/8" crank, or 665" with 5" crank. Just not sure what the down side of all that air flow would be..

Thanks
Dick

Re: 604ci or 572 ci
 

Dick I don't know but I am sure you can call Richie or PM JC perf. and he can tell you. Take care, Steve.

Re: 604ci or 572 ci
 

598 is probably the best combo for a NA motor.When you go bigger with a chevy style cylinder head they make torque but the power doesnt pick up like you would think.When you put that big arm in an engine the piston speed increases and the engine runs out of air.If it was my choice i would go with a 598.It should make peak power around 5700-5800 if the cam and heads are not monsterous.

Re: 604ci or 572 ci
 

604 @ 5300= 4195 ft/min of piston speed
572 @ 6000= 4500 ft/min of piston speed
This means their is more stress on the bottom end with the 572 at 6000. Piston speed is the speed the piston travels while you are at a certain rpm and yes the more the stroke the faster the piston travels in the same rpm which is harder on parts----rods, cranks, bearings.
604 @ 6000= 4750 ft/min
572 @ 6334= 4750 ft/min
this is the same amount of piston speed for both motors.
As far as breathing the more stroke will always have more average torque through the rpm band.