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Old 05-19-2010, 12:46 PM
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RPM RED LINE sbc???????

What is the approximate RPM RED LINE for a 350 small block chevy putiing out 350 horse power???

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Old 05-19-2010, 12:54 PM
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Originally Posted by 40forddgc
What is the approximate RPM RED LINE for a 350 small block chevy putiing out 350 horse power???

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Its approximately a little below how many it takes for the engine to self destruct.


There is no other appropriate answer to such question.
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Old 05-19-2010, 01:04 PM
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Feel better AP...you got one over on that guy didn't you? If you aren't patient enough to ask him the right questions to help him out...shut the hell up
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Old 05-19-2010, 01:14 PM
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Quote:
Originally Posted by 40forddgc
What is the approximate RPM RED LINE for a 350 small block chevy putiing out 350 horse power???

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Lots of factors to take into account. Allot of what determines "redline" has to do with the valvetrain. Stock valve springs and a stock cam won't be doing much over about 5k rpms. More cam and the valve springs to go along with it will up that number. Of course the condition of the bottom end ie: stock rods vs aftermarket also play into the equation but no so much having to do with where it stops making power but where the parts start to come apart.

A typical 350 horse 350 with good rod bolts and mild hyd cam with fresh valve springs probably has a redline in the 6000-6500rpm range but would more than likely stop pulling by 5500.
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Old 05-19-2010, 01:15 PM
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Quote:
Originally Posted by 40forddgc
What is the approximate RPM RED LINE for a 350 small block chevy putiing out 350 horse power???

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It really depends on your engine. Some people will say "I ran my stock SBC at 6500rpm every day and it held together just fine". Others will say they threw a rod at 5k. I had a 305 SBC that I was getting ready to send to the junkyard in an 83 Camaro and it took 6500 rpm for about 30 seconds with NO OIL before throwing a rod. Doesn't mean yours will too.

I have to ask, what is your specific engine setup (cam, heads, intake, etc.)?
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Old 05-19-2010, 01:20 PM
How fast is fast enough?
 
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It'll always be a crap shoot. On a stock sbc usually the valvesprings limit it, but sometimes a bolt or a bearing will give out first. If its stock there's not need to worry about it anyway- depending on the combination you're better off not revving it to the moon if you want to go fast.
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Old 05-19-2010, 01:51 PM
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red line sbc

thanks for the reply. I am running a Isky Mega cam, with a high quality roller rockers.
cam lift .323
valve lift .485
duration 280

4 bolt main
World street heads
675 edlebrock carb
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Old 05-19-2010, 01:55 PM
How fast is fast enough?
 
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Quote:
Originally Posted by 40forddgc
thanks for the reply. I am running a Isky Mega cam, with a high quality roller rockers.
cam lift .323
valve lift .485
duration 280

4 bolt main
World street heads
675 edlebrock carb

Are you wanting a redline for the shift point or a DNE unless you want broken parts red line? If its for shift points then post your entire engine spec list, the trans,and stall.
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Old 05-19-2010, 01:58 PM
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Call your cam company with your combo and tell them instead of listening to a smart-a, knowitall like AP. You'll be glad you did.
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Old 05-19-2010, 02:00 PM
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rpm red line

Thanks..... AP thinks he is a know it all. Obviously he isn't.
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Old 05-19-2010, 02:14 PM
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What sort of parts are in the bottom end? Compression ratio?

Isky lists that cam as 2500-6800 rpms
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Old 05-19-2010, 04:57 PM
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Assuming the valvetrain can support 6k+, the next limiting factor would be rod bolts and pistons (cast vs hyper vs forged). Limit for stock-type cast pistons would be around 5,500rpm AFAIK. Hypers should be good to around 6,500-7,000. Stock rod bolts are safe to 5,500-6,000 but you'd want ARP bolts for anything more. I reckon 6,000rpm is a good redline/shift-point on most street/strip combos. I rev my 383 to 6k, but did accidently buzz it to 6,500rpm just the other day... thankfully, it held-up, but if I were to do that to it on a regular basis, I'm sure my luck would run-out pretty quick!
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Old 05-19-2010, 06:09 PM
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Quote:
Originally Posted by 40forddgc
What is the approximate RPM RED LINE for a 350 small block chevy putiing out 350 horse power???

Thanks
Assuming the valve train doesn't stop the engine from continuing to rev, the limit will be set by the rods. Rods usually fail thru the bolts or thru the shank about a half inch above the big end. Stock production 350 rods will take now and again to 6 or 6500. But this is never a sure thing, high revs should always include a certain amount of pucker factor on your part.

The pink rod is good for about the same rev range, but will do it more often and for longer. They start as selected from the best of the best production rods. Then they get the bored for the larger 3/8ths bolt, beam polished and shot peened, heat stress relieved, then magnafluxed which leaves a pinkish residue hence their name. This is as good as it gets for a 1000 series steel, which is actually pretty damn good. Real pink rods are these:

Part number 3927145, small journal, pressed pin

Part number 3973386, large journal, pressed pin

Part number 3946841, large journal floating pin. The Chevy production rod really doesn't have enough meat in the small end to accommodate steel removal for a bushing and still have enough strength to support the pin. Chevy did a small over bore in thousandth's of an inch and plated Babbit into the hole and honed it to size. In pro race motors this proved really problematic as the Babbit was quickly pounded out loosening the pin which then pounded itself and the pin hole to death. Stay away from these if you find any.

Buy now you should realize from the quantity of Pink Rods you see advertised in the catalogs there's more pretenders than were ever made by GM. Taking a stock rod, polishing the beam, stuffing a 3/8ths bolt into it, resizing the big end and calling it "Pink" ain't the same thing, though it's probably an improvement over bone stock.

Used rods, rebuilt or not have already given at the office, the older they are the less they're likely to stay in one piece. Rods and their bolts are prone to
fatigue failures from age. Under the power stroke they see compression of the metal and bending/buckling stresses. Going over the top on the exhaust stroke and down on the intake stroke they see those forces reversed and are under tension (stretched). This causes what's called inter-granular corrosion which leads to the type failure you see in a paper clip when it's bent back and forth.

350 horse is pretty moderate for a 350, for the most part you can take that to 5800-6000 fairly often if the rods are known to be good and are pretty new.

Bogie
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Old 05-19-2010, 06:10 PM
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RED LINE sbc

Thanks to all. The info was very helpful.
Doug
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Old 05-19-2010, 06:55 PM
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Well I will throw my two cents in here. Ten years ago I had my first SBC 350 which was all pretty much stock with a rv type cam and it pulled strong all the way till about 4800 rpm and then just leveled off so that was my redline was 5000 rpm because of my camshaft profile and I had the old 882 heads which are crappy anyways. I then did a rebuild with a bigger cam and got different stuff to go with it and it would pull to 6000 plus but I never took it that high. I only had stock rods with stock type bolts so never trusted them that much over 6 grand.

From my Father who has built many SBC's over the years stock rods are good to about 6000 rpm but you don't want to keep it that high for an extended period of time. With ARP bolts they will take a little more but there still stock rods and will eventually give if they have been used for many miles. Many circle track racers have used stock rods and they see 6500 rpm's for many weeks and last many years as well so many other factors will come in as well.

4340 forged rods with cap screw type bolts will take a little more rpm's then the through bolt design. If you get the H beam type rods with the 7/16 cap screw bolts they are good to 8 grand which is overkill for a daily driver type deal.

If your rods have been on a motor that has over 150,000 miles I would not want to trust them reeving way high for too long. I have a brand new scat rotating assembly on both of my 350's and they could take 6000 plus no problem but to be safe I never take them above 5500 rpm. I want to keep my motor together not worry about every last horsepower I can get.

Eric
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