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Discussion Starter · #1 ·
I am hoping to buy some cams in the next few months or so, but I won't be replacing my internals for a bit. Anyone know what the safe rpm limit of stock internals?
 

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6200...beyond that and you risk valve float with stock cams...with aftermarket cams and no new valve springs, i would say 6000...to be safe. i was at the top end of third and threw my car into second the night i got it and overrevved the motor to like 7800 or so...destroyed cylinder 6 top to bottom
 

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Discussion Starter · #3 ·
6200...beyond that and you risk valve float with stock cams...with aftermarket cams and no new valve springs, i would say 6000...to be safe. i was at the top end of third and threw my car into second the night i got it and overrevved the motor to like 7800 or so...destroyed cylinder 6 top to bottom
Oh yeah, I forgot to mention I will be replacing the valve springs. I'm talkin' about pistion, rings, and moslty (those POS) rods. I'm hoping to at least be able to go 6500 rpm.
 

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6200...beyond that and you risk valve float with stock cams...with aftermarket cams and no new valve springs, i would say 6000...to be safe. i was at the top end of third and threw my car into second the night i got it and overrevved the motor to like 7800 or so...destroyed cylinder 6 top to bottom
I did the same thing but I think I must have a rev limit set because it didn't damage the engine but blew a charge pipe off.
 

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6200...beyond that and you risk valve float with stock cams...with aftermarket cams and no new valve springs, i would say 6000...to be safe. i was at the top end of third and threw my car into second the night i got it and overrevved the motor to like 7800 or so...destroyed cylinder 6 top to bottom
:eek:
The rev limiter doesn't help at all when you're down shifting. I did that to a 69 Camaro once.:(
 

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I think its more related to cylinder pressure than rpms. If you throw a lot of boost in the mix it wont last long and could blow at 3000rpms. The heads will probably limit the power you make to around 6K. spinning faster may not yield more hp. With no pressure on the internals you could spin them WAY up in the rpms without them blowing apart.
 

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i was debating this same question. good topic lol

in about a month ill have a complete new top end, cams, springs, valves. P&P heads etc.

what would be the limit of reving the bottom end to?
 

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MM's Mad Scientist
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I took my stock bottom end to 6500 and beyond on good cams and comp springs. 6500 should not be a problem at all.
 

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these motors are known for spinning rod bearings I would not recommend much over 6000.
 

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depends all on set up. if valvetrain is set up to handle it, it will spin high enough to make most people worry.
 

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You guys are gutsy. I dont take mine past 6K. When i get my car tuned I dont even plan on having them raise my rev limiter. You dont really make any power up there anyways.
 

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MM's Mad Scientist
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You guys are gutsy. I dont take mine past 6K. When i get my car tuned I dont even plan on having them raise my rev limiter. You dont really make any power up there anyways.
This is an old dyno sheet from my car with the stock short block, mildly ported heads, and Comp 270 cams. As you can see, 6500RPM's was the perfect shift point to keep me right in the sweet spot after shifting.

 

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Discussion Starter · #16 ·
You guys are gutsy. I dont take mine past 6K. When i get my car tuned I dont even plan on having them raise my rev limiter. You dont really make any power up there anyways.[/quote]
That's what cams are for:eek::)
 

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Discussion Starter · #17 ·
This is an old dyno sheet from my car with the stock short block, mildly ported heads, and Comp 270 cams. As you can see, 6500RPM's was the perfect shift point to keep me right in the sweet spot after shifting.

Man that is solid!:eek:

One of the best dynos I've seen. That's what I'm trying to accomplish. Peak power at ~6000 rpm with a steady roll off making for a perfect shift at 6500 rpm.
 

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MM's Mad Scientist
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Man that is solid!:eek:

One of the best dynos I've seen. That's what I'm trying to accomplish. Peak power at ~6000 rpm with a steady roll off making for a perfect shift at 6500 rpm.
Well, I built it to make steady TQ through the power band, and I was successful. It pulled great on that set up. However, all good things must come to an end.
 

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Discussion Starter · #19 ·
Well, I built it to make steady TQ through the power band, and I was successful. It pulled great on that set up. However, all good things must come to an end.
:confused:
 
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