RPM you can hit before you blowup

[chevyc1068]

What do you think the RPM threshold is for these engines. I'm talking a rebuilt 307. What RPM can you get to before you start to do damage to your engine. Because i have a 3.73 rear end in my pickup and if I ever want to see what kind of speeds I can reach and how fast I can than I need to know what RPM I need to stop at before I start damaging. I know that at 60mph it'll only be about 2300-2400RPM. Are we talking 5000 or is it 6000 or is it only like 4000?

[1BadSS]

I used to hit 7200 daily in my old 327.

[TooT]

I've ran mine up to around 6200 maybe 6400....it's a built 355. I'm not gonna try to get it anymore than that....just the thought of it blowing up

[corn]

I knew a couple guys that ran them back in the day. They didnt do a whole lot of hi-per stuff to them & they twisted the sh1t out of them. I dont really know why you would want to though.

[watahyahknow]

the short stroke 302's ran up to 7500 rpm the bigger the stroke the less rpm youre willing to run because things get heavier flinging oround in a bigger circle

[my67C10]

well it really depends on what you have done to your engine, Formula 1 engines rev up to if not higher than 19000 rpm.302 is around 6500 327 i would say around 6300 at MAX, 350 around 6K, the 402 around 5700. if you blueprint your engine i would expect around 1.5 times thoes stats if you get high rev valve springs and a free flowing intake and exhaust i would say add another 1000 to each of thoes. what kills your engine at high RPM is the engine starts to lean out from lack of flow.

[my67C10]

i know that pickup truck diesel engines rev to like 3200 MAX RPM (stock) ive seen a few diesel engines rev up to 5K and let me tell you what, that is expensive to get them to rev that high and the HP is amaising and the tourque is unbelievable not to mention how a diesel sounds when its revving that high, it sounds like an import rice burner and a diesel combined.

[bigjimzlll]

You might not be old enuff to remember...but there used to be an old Tootsie roll comercial on TV. It had a wise old owl that a kid brought him a tootsie roll pop and asked " how many licks does it take to get to the center of a tootsie roll pop"? The wise old owl says lets see...He takes one lick...then two licks...then he bites the tootsie roll pop and says...It takes 3 licks to get to the center of a tootsie roll pop.

My point is, a vague question like yours is difficult to answer. High rpms are cumilative<sp> You might go to 6500rpm a dozen times with no ill effect, but each time you take a little life away from it.

A stock 307 I would limit it to 5000rpm(you wont make any more power after that anyways) If you want high rpms...build it too rpm.

The 302's and some 327's that saw high rpms stock had good valve springs, solid flat tappet lifters, forged crank and better rods(pinks or "X").

[speedracer]

my 327 over 7000, I tryed to blow up the 307 I had in the truck before. I held it floored in neutral it hit 6100 and wouldnt go any farther after about 5 minutes of that I gave up. I pulled the heads off after and the valves were white from the heat I'm still curious how much more it could take before it let go. I think the cam or the dissy was holding the rpm's from going any higher the lifters were starting to float too.

[C10-Driver]

I have a decently built 350 in my truck. I recently installed a used factory tach (5000 RPM max). Based on where the tach tops out, how the engine sounds and how much further I am able to push the engine comfortably I must be getting 7000 easy. I can't confirm this but it doesn't surprise me because I had a 5.3L in my 2001 Silverado and it was nothing to get that motor up to 6000-6500 with the transmission in drive. If the computer controlled transmission allowed the motor to rev that high before shifting, GM must think they can run there daily without blowing up.

[caseychoptop]

i have a 400ci 6.6 litre smaalblock, in my 69 c10, would any one know what sort of revs this could do

[my67C10]

i would stay under 5500

[VetteVet]

Anything over 70 beats per minute is critical for me. LOL

[chevyc1068]

So what can you do to an engine to have it be able to run at higher RPMs? What kind of things do you need to add or change? I don't want the engine to run fast I just want it to be able to withstand higher RPMs.

[bigjimzlll]

The valve train is first limiting(mechanically) obsticle<sp>. The intake and heads can limit rpms too. The rotating assembly also has mechanical limits.

If you upgrade the valve train with better springs and cam and lifters the engine will have the potential to rev higher if the heads will let it. If the heads and intake are too restrictive it will limit the rpm...but wont hurt the motor, just wont let it rev.

The internal components have limits too. Better rod bolts will allow higher RPM's. Aftermarket rods are a better solution. They are not 35 year old forgings that have been abused a million times. The stock cast crank and pistons are also rpm limited, but not as much as stock rod bolts. None of the internals will make the engine rpm more...but allow it to live while reving higher.

Valve train and induction are the key to higher rpms.

[corn]

Im doubting you invested a ton of money on the 307 engine, so if you keep it below 5000-5500 it should last a long time...What does a diesel, formula one, or import have to do with a 307 sbc? How do simple questions get drawn off course here so fast?

[layedoutnoma]

just floor it till the hp drops up top and subtract a few hundred rpms and there you go... ha works everytime

[lilpup69chevy]

i'd say it would hold 6k safely the redline is suppose to be around 5500 i believe

[slt0066]

if you want to turn alot of rpms and not damage any thing you should look in to a set of roller rockers , lifters and cam bearings

[Bad71chev406sbc]

350...in a friends truck.....7900 rpms. Amazing what a vaccuum line off the trans will do.

[TooT]

Originally Posted by Bad71chev406sbc

350...in a friends truck.....7900 rpms.

thats crazy...

[wolfthing2000]

383 5500 I was told by my engine builder.............unless you wanna spend some big bucks on heavy duty bottom end upgrades. I am sure it will run higher without any problem, it is just that the pooint is all about efficiency , power and keeping your engine in the truck and off the engine stand the longest mileage possible.
But if you race.................anything goes, just be prepared to work on em and spend the bucks!

[crazy longhorn]

I wouldnt spin the stocker past 5500-5700.....& I doubt you will be making power past 5000, so in all reality there is no point revin higher than that. A good built /balanced small block, should have no problems in the 6500 rpm range( cast crank, stock rods/w good bolts, & even the cast pistons will live, assuming you dont road race). the top has to be "spot on", as well as the balance on the bottom to hold together. I have seen a stock bottom (high mile) 307, with 300 hp 350 heads/4 brl/headers run 6500.....but who knows how long that will last? I have seen my 383 @ 7200 a few times....not on purpose, but the gears crank her up FAST! Its hard to keep the tach under 7000, for the first couple gears. The 383 ( built & balanced), should be shifted @ around 5700......but she is still makin power @ 6500.....the complete mess might go BOOM one day, but fun while she run L

[bucket]

[QUOTE=bigjimzlll;1877035]You might not be old enuff to remember...but there used to be an old Tootsie roll comercial on TV. It had a wise old owl that a kid brought him a tootsie roll pop and asked " how many licks does it take to get to the center of a tootsie roll pop"? The wise old owl says lets see...He takes one lick...then two licks...then he bites the tootsie roll pop and says...It takes 3 licks to get to the center of a tootsie roll pop.

LOL...I loved that add. i remember thinking that if that owl would have eaten my pop i would have kicked it a&*.