How many RPM\'s can it turn!!?

[s10trev]

Hey guys.....got a question for ya. I have a 355 with hyper pistons and a nodular crank...good valvetrain and a 244@.050 flat tappet cam. How many RPM\'s can I turn before that crank comes apart? It\'s a fairly new motor, all ARP stuff and I havent had it over about 5600. It really wants to go more, but I want to know the limit before I find out the hard way......Also....this is only in a weekend toy so I\'m not worried too much about getting some 100,000 miles out of it...



Thanks

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[bohn333]

I wouldn\'t run it past the rpm of your cam, i wouldn\'t go past 6200 to 6500, but i ran my stock bottom end to valve float several times at 6800rpm and nothing happened. Take it to 7,000, it will float the valves before the crank comes apart.

[link523]

i have about the same motor and i would say under 7000 also had mine to 8000 once long as you dont use nos it should be fine for a long time

[fasrnur]

I have a cast crank in mine and have bounced it off the 6000 chip in my MSD a few times and still going strong. With the crank you have I wouldn\'t be afraid of 7000. It should be safe there in my opion.



Jeff....

[spacecadet]

I had built 350 and ran in my ta. I use to twist it up to 7000 regularly. (Pull FL wheel of the ground!) Everbody told me not to rev it over 6000, but I did anyways!

Check for max rpm with the other parts in your motor. An other piece may have a lower rpm rating on it. Then either abide by it, replace it , or Rev it untill it doesn\'t break.



BUT --- As with any mechanical item,



An engine is only a strong as it WEAKEST part!

[ZZ4Blazer]

Depending on how well your heads flow, your cam should hit peak around 62-6500. I wouldnt push past that. Your just asking for trouble.

[speeder]

If you are out of balance the high RPMs can hurt very fast, so just be careful. I would work my way up to whatever you are going to hit.

[Knanthrup]

Just turn it to where you\'re making max power with that cam. Doesn\'t make any sense to go past it anyways. Not much over 6 grand should be good.

[s10trev]

cool....I\'m getting ready to take my longbed and making it a shortbed/tubbed/9 inch rear with a ladder bar setup. Hope to have it ready to race and drive by the end of spring. Thank you guys very much for the info.

[OBE]

When it comes to RPMs and power, you must make sure that your valves are doing what they are supposed to be doing and when they are supposed to be doing it. When you rev your engine past what your valve springs are designed for, you get valve float. Don\'t take that lightly, valve float is serious! The valves are literally floating off their seat. If you spin your engine past what your springs are designed for, your springs cannot control the valve and they will violently bounce off their seats and that will eventually weaken your springs prematurely which will lead to float occuring at an RPM that you might not be used to and at the most extreme... valve to piston contact!!

Pick your parts for who is going to drive it, where they are going to drive it, and how hard they are going to drive it. If this is your daily driver choose wisely, you\'ll be much happier.