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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.

Mr Gadgets

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

Nykamp

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.

JCPERF

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.

NOBODY

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.