As the motor is breaking in more I am becoming more daring with the RPM band. I researched a formula where the authority issued these general guidelines- If you want to find your safest red line RPM you must first find the travel of the piston in Feet Per Minute. The formula listed was (X * Stroke)/6; where X is a given RPM. That number should be >4000 FPM in mild street car. I was pretty satisfied with that but then I started to wonder how much the factors of piston weight and ring tension play a role.

So my question(s) to the street/strip or aggressive cruise crowd are-

-What are you spinning your 350 up to?
-Have any factors been blue printed into your build to off set high RPM risk factors?

 

In my experience the red line needs to take into consideration all the components in your build. In most cases the SBO is limited by the cam and valve train on a stock to mild build with hydraulic lifters. I would not spin a stock or mild build more than 5200-5500 rpm.

 

I cannot speak to the RPM limits of Olds. I do not see how a formula could be applied to all engines as they are not created equally. The engineering, quality control and design differences between them are varied.

 

Well I broke my new engine in at the track. It is not a sbo it is a bbo. 5500 was as far as i went in drive. I have four passes on the engine. Next time out i will be shifting to see how it responds. I am held up for lack of funds no job.

 

I agree completely. It also got me doing some deeper thinking, such as, what is mild?

 

Big difference between engines. The mass of a big block crank to me makes 5 to 5.5K RPM close to the pucker factor on a stock rod and crank. But I would take a stock Mopar LA small block to 7K without worry, and did. Look at the RPM the 4 and 6 cyls can turn. Its all about the RPM a engine has its' most power at, not how high you turn it.

 

I used to run my basically stock 350 with a hotter cam to 5800 RPM but that was with a different setup that actually made power up to that point; now my redline is ~5400 RPM.

 

X2. I've found this is a very safe red line. OLDS motors like low red lines. They are high torque low rpm engines. Be careful.

 

You can float valves, run out of oil, throw apart a not-too-balanced or overly heavy rotating assembly, or rip the main caps out of the block before throwing that assembly. Mitigating factors to address all of those are built into performance engines, along with a lot else.

 

I was talking to my buddy tonight about my Cutlass. He said when he drove it, it pulled right into the rev limiter at 6000 RPM. Then the rev limiter kicked in and he thought he had broken the motor. We laughed and I said that's why I have rev limiter on it! I like 5200 myself. Safe.

 

I think red line is much more involved then some formula. Bob weight is probably more important overall. I've personally taken my BBO to 6700 rpm. It did have Venolia pistons but it's not an RPM I recommend. I typically did 5700 max when at the strip. The valve springs seemed to give up after that.
Just so much more to this to explore. I've seen SBO guys go 6500 all day.
The cam will tell you when it's all over. If the cam manufacturer lists 5400 as it then stick to it

 

Back in early 70's when I was racing my w31 I would spin it to 6300-6400 rpm's with no problems. This was with the factory 308 cam and springs. I placed .040 spacers
under the rocker pedestals which would give the lifters more travel to help avoid lifter pump up. I would also keep a close check on spring tension. All necessary as I was pulling 5:00 gears. It would get tight in the traps. Really didn't have a rpm limit "JUST TURN IT TILL IT SQUEALS" HA!

 

I shift at 6300 rpm and by the time I shift it on the light it comes in at 6500 rpm. The small block olds can rev to the moon in a hurry. They like to spin .

 

When it was still under "GM" warranty, 6200 was the favoured shift point. 40 years later under "owners" warranty, it's 5800 due to "monetary restraint."

 

Hehe! I still have a 6k chip on my semi-high-zoot 468. I'm scared to death of blowing it up. Then again, stock EBrocks will probably float the valve train.