440 HP RPM redline

[Bobby Sixkiller]

I used to shift my 440 at 6200 when drag racing. My uncle always claimed he shifted his at 7200. Those were built race only engines. Lots of head work. Forged cranks. That said. Anything on the street probably doesn’t need to go past 5000. IMO

 

[BSB67]

View attachment 844783 5500 rpm.

That's not because of rpm. Faulty part or............

 

[1 Wild R/T]

That's not because of rpm. Faulty part or............

Probably to long....

 

[Wietse]

Just out of curiosity, did Chrysler not do any road/dyno testing on them engines back in the days?
They engineered the engine, but after building a few the manufacturer does road testing etc. right?
Like they do now days.
Guess that includes a session of running at max rpm, or exceed it and see when it blows?

 

[BSB67]

The subject of red line and max rpm seem to come up frequently. As simple as those terms seem to be, there should be some narrative describing exactly what that means to the person asking the question. To some it might mean:

1) the highest rpm at or before failure, and these might be different for sustained rpm verses acceleration runs.
2) the rpm shift point for best acceleration runs
3) the rpm that the motor will no longer pull.
4) the rpm that the factory chooses to minimize warranty claims.

Here are my opinions based on observation:

For number 1 - seems like back in the day LY rods with 1100 gram piston/pin would give it up in the low to mid 6000 rpm range. The factory upgraded the rod after the 4 speed 69 Six Pac cars were having more rod failures.

For number 2 - as other have suggested, probably 5200 rpm

For number 3 - Probably about the same as #2, maybe 5400.

For number 4 - I don't know.

383s and hemis are way different, so the numbers would be different.

 

[Dennis H]

That's not because of rpm. Faulty part or............

Was in for 60k miles. Failed on first romp over 5k.

 

[66Satellite47]

Dennis H, IMHO you some valve train issues. My stock 383 low CR orig 2 BBL, (converted to DP4B/3310 Holley, headers, Accel points) went well past 5000 RPM many, many hundreds of times, never broke anything, 110,000 miles. My drag race 440's with heavily ported 906 heads & big cams went many hundred runs over 7000 RPM. Stock steel cranks do start showing cracks after 350-400 runs over 7000 RPM. Never broke one though, or the shot peened LY rods w/SPS bolts. Adjustable rockers also wear over 7000 RPM. Parts live just fine at less than 6500, in my opinion.

 

[74gtx]

Mine seems to give up around 6500. It’s a stock 440. It has seen 7000 many times. I have an issue with my 1-2 shift so unfortunately she gets up there quite often. I think 5500-5800 would be ideal for them in a perfect world though.

 

[Mike Szadaj]

So back to the original question, what did Mopar say the redline was for big blocks?

 

[dvw]

The limit on rpm for power on a stock 440 is around 5000-5500. Better heads a cam and it"ll make power higher. The real issue isn't the crank or the rods. Its the piston. The compression height of a 440 piston is close to 2". That makes them heavy. It's also why it's easy to stroke one and use a long rod. My steel rod 572 (4.500" stroke, 7.100: long rod has a bobweight of 2222 grams. Compare that to a stock 440 at close to 3000 grams, 1.76lbs per cylinder greater weight. Weight squares when rpm doubles. 1000 rpm1.76lbs, 2000, 3.09, 4000, 9.56, 8000, 92.06. That's just the weight difference. Tie a 92 lb rock to a string and swing it. That's why the stock rods fail.
Doug

 

[wyrmrider]

I've worked with some of the "NASCAR" longer than hemi length "chrome moly" rods- impossible to find but I have samples somewhere
my take
LY rods, side ground, shot peened (mil spec not wheelabrator or shot blasted) with DC/MP SPS bolts are best you can do with stock rods- forget the 6 pack rods
go longer with lighter pistons helps the most, even with a stroker
The big end of the rod fails before the SPS bolt- with stock bolts they may go first but
Usually something else went first like a dropped valve
what DVW above post said

 

[BSB67]

So back to the original question, what did Mopar say the redline was for big blocks?

I've never asked Mopar, and they've never called me to tell me either.

 

[Wietse]

I think if you look at the tach in your dash the answer is right there, guess where the red line starts Chrysler leaves it up to you where to stop.

Think them days i think it went by trial and error what these engines could handle, then they also must have found out each engine is likely to be different and some can handle more then others.

 

[Ceedawg]

I find it funny that many used to ditch the heavier Six Pack rods and just use regular 440 LYs when the factory specifically designed the 6P as the stronger units.

Good beefy rod but keep the little bolts and cap. Could have just used the Hemi rod at .0100 longer @ 6.86 and saved a lot of money.

 

[wyrmrider]

good beefy rod but std steel, so it bends
The could have used a longer rod and lighter piston and saved lots of motors
I have rods with 7/16 and Half inch bolts from the 60's wedges

 

[66Satellite47]

To OP, factory "red line" is whatever the factory tach says. I'm not sure. The realistic "red line" for a stock 440 is about 5500 Rpm, you got no power above that, 5000 is probably the best. As for con rods, LY aircraft shot peened with good bolts work to 7000 RPM. I ran some at 7200 - 7300 for hundreds of runs. No problem. The 6 Pak rods are just heavier. The Hemi rods, bigger beam, contoured small end, bigger bolts, (better steel?) much stronger. But lighter piston is still a key thing.

 

[Mike Szadaj]

I understand that my car came with a tach with a 5,000 rpm redline, but I was wondering if there was back in the day printed redline figures for the 383, 440, and Hemi just like there were for HP and torque.

 

[66Satellite47]

Not that I recall. Just what the DC Bible advised. Which I totally ignored.