What RPM is Redline for a 1972 - 400 engine?

[rumblefish360]

LOL @RemCharger , thanks.

Depending on what shape the engine is I would say 5500-6000. No reason to shift above 6k. Usually shifting a couple hundred rpm higher then power peak helps keep the car in its power band...unless the valvetrain is unstable.
400, RPM heads and intake, 703, headers, 9:1
Generated w Dynosim 5+

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Funny! That’s the curve I had in my head.
What cylinder head or flow figures did you or the computer use?
The RPM’s?

 

[hdwrench]

looking at the curve i would think of shifting around 5800 when the torque is on the down curve .

 

[rumblefish360]

looking at the curve i would think of shifting around 5800 when the torque is on the down curve .

That’s called short shifting. You’re leaving a lot on the table in this method. To travel the quickest, a few hundred rpm past peak is what you’re looking for. Otherwise, it depends on the HP curve, or lack of past peak HP to determine where you shift.

When the HP curve falls (dependent on how much and how fast) you want to delay the shift to stay in the highest part of the HP curve and not the torque curve. Travel in the fattest part of the HP curve.

 

[Dennis H]

Get a Chassis Dyno and see when it levels off. My 440 stops pulling before 4900. There is no reason to go there. I just upshift. Rods first to compromise on mine. Go to the other thread where owners want their BB to wind like a small block.

 

[toolmanmike]

Red line? Shift points? A dyno curve would tell. I have seen it done but haven't figured how to do it yet. (I have no need) RPM drop into next gear and where it lands in the torque and horsepower band. AJ/FormS over on FABO has got that down. It's an interesting theory.

 

[4mulas]

The actual limiting factor is not the rod, but the wrist pin slipping out of bore from heat, from years of 7000 7400 bracket racing experience with a lowdeck. The pin locks up in the bore forcing another rod to " dislocate".


No lowdeck rod is coming apart at 5500. Just saying.

I didnt say they were coming apart at 5500.

He asked where to go for a redline and I suggested 5500. At 226 duration I imagine that’s where he’d be in the meat of the power and it would flatten and taper off after that. Some rev limiters seem to come in early, so if it’s set at 5k it may start popping around 4700 kinda thing, so for the OP keep that in mind. If you’re looking for a clear clean 5500 shift you may have to set the limiter a little higher.

I wouldn’t go over 6000 on a stock rod on any motor that I cared about.

 

[Curiousyellow71]

LOL @RemCharger , thanks.

Funny! That’s the curve I had in my head.
What cylinder head or flow figures did you or the computer use?
The RPM’s?

Yes, The program has a rpm on file. I don't have the specifics as I am away from it. But I recall they flow in the 280s max and includes the lower lift flows. They are measured flow #s for a actual bb edy Rpm.

 

[1967coronet]

Over 6000 ? To me there are to many unknowns , the B engines will or should hold up down below if in solid shape and decent oil supply.
Push rod length ,pre load, coil bind , lifters ?
Ignition ? You don't want that girl farting at 6500.
I used to try judging by rpm drop at shift points.
If it's pulling good the rpm were the engine drops the least amount of revs is what I used to go by.
Not very scientific I know.

I would dbl check everything up top before reving to spec sheets.

 

[INTMD8]

Get a Chassis Dyno and see when it levels off. My 440 stops pulling before 4900. There is no reason to go there. I just upshift. Rods first to compromise on mine. Go to the other thread where owners want their BB to wind like a small block.

That's one way of looking at it. Or you could say, may be something wrong with it (valvetrain unstable?) if it peaks at 5250 and drops off hard afterwords.

 

[Myasylum]

Ok, Thanks guys. The springs are what come with the RPM heads.
From what I have read...

Springs are 120 lbs on the seat at 1.80 installed height and
320 lbs opened....at .575

Cam
Duration at 050 inch Lift
226 int./234 exh.

Performer RPM Intake

800CFM Edelbrock AVS Carb

It's a torquey fast revving engine, part of the reason I want to keep and eye on the RPM's.
I will reset the rev limiter to 6000 and see what happens. Unfortunately, I now have to wait till Spring.

I did go up against a flat 6 (non turbo) Porshe Cayman S and beat him... I can't be doing too terrible.

 

[hdwrench]

That’s called short shifting. You’re leaving a lot on the table in this method. To travel the quickest, a few hundred rpm past peak is what you’re looking for. Otherwise, it depends on the HP curve, or lack of past peak HP to determine where you shift.

When the HP curve falls (dependent on how much and how fast) you want to delay the shift to stay in the highest part of the HP curve and not the torque curve. Travel in the fattest part of the HP curve.

peak torque or peak horsepower?

 

[Kern Dog]

I won't run that engine with a HV oil pump if you're using the stock 5 qt. pan. You run the risk of sucking it dry. I would try 5500 and if the seat of your pants dyno feels like it's still pulling try a bit more. I would think you'll be out of usable power around 6000 rpms.
Ron

That is an age old myth that gets passed around by armchair quarterbacks that are like the following illustration:

Nobody runs at a continuous 6500 rpms on the street where this rare occurrence might happen.
Momentary blasts to 6000 rpms have zero issues with an engine that isn't all sludged up. The Mopar engines have excellent oil drain back.

 

[INTMD8]

peak torque or peak horsepower?

You want to ride the bubble of max average horsepower which would start by shifting 10% rpm higher than the rpm it makes peak horsepower.

(so the horsepower it makes at the top of the gear is the same horsepower it will make entering the next gear when rpm drops)

 

[33 IMP]

A 5000 redline is very safe, but limiting performance.
Otoh, peak horsepower for a hi performance 440 was rated at 4700 to 4900.
You have a bit more cam than a stock 440, and much better heads, a bit better intake. My guess? I think it'll make power to 5500, I'd shift it at 5800, I seriously doubt you'll do any damage there.
My 440 with worse heads, lots more cam, spins safely and easily to 6500. But, It doesn't make power there! I used to shift at 6200, but I found it goes just as fast and quick, shifted at 58-5900.
Best suggestion? Get a performance app for your phone (draggie, or something like that, spelling might be wrong) and try shifting 1-2 at 5500, 5800, and 6000, running to 330 feet, and see what is fastest.

 

[1KoolBee]

I’ve seen 383’s endure sadistic abuse with no bottom end issues. Mine included. 6000+ in a 400 should be no issue if stock bottom end is in good shape (add good rod bolts) and valvetrain is up to snuff . Consider aftermarket rockers if you’re going to really rev the sh*t out of her.

 

[RJRENTON]

I won't run that engine with a HV oil pump if you're using the stock 5 qt. pan. You run the risk of sucking it dry. I would try 5500 and if the seat of your pants dyno feels like it's still pulling try a bit more. I would think you'll be out of usable power around 6000 rpms.
Ron

WHAT WAS YOUR THE REASON FOR THE RED X RE MY POST #9 and the high volume oil pump? Do you not understand the concept of the hydrodynamic oil film theory on a journal bearing? I've had a high volume oil pump on my '70 GTX RS23VOA****** for 35 years and a stock oil pan, which i run one quart over full with a windage tray and NEVER HAD AN OILING ISSUE. I run 0.002" - 0.0025" on the main and rod bearings and the mains are full groove type Clevite tri metal bearings for mains and rod bearings. With a std volume oil pump at higher RPMs, you run the risk of spinning a rod bearing due to inadequate oiling.....it's your engine....do what you want.....an HIGH VOLUME OIL PUMP is good insurance against bearing failure. Or are you just parroting a buddy or someone else ??
BOB RENTON

 

[Kern Dog]

It is like I stated. Typical guy that repeats what he heard at a car show somewhere, spoken by a person with zero direct experience.

 

[Myasylum]

I did buy a HV oil pump, but never put it on, because of what I was told. That is without a windage tray, and stock 5 Qt pan I'd be starving it of oil at high RPMS, so I left the stock oil pump on.

Seems there are two different thoughts on this subject.

 

[Fury63]

Stock oiling on a B engine is about as good as it gets. HV oil pump is very much just a good way to heat the oil and stretch the timing chain. Don’t need or want an argument but, the only way I would get on the over-oiling train is, if I have a 10 quart oil pan full of 20w/50 and most door cars don’t have that luxury.

 

[RemCharger]

I have been very lucky and fortunate to not stretch timing chains or heat the oil ( which inherently gets hot in an engine as its designed and intended) because of an oil pump rotor that's a few hundred thou taller.
If it ever happens I will be back here to update.