What RPM is Redline for a 1972 - 400 engine?

[Myasylum]

I have RPM Heads which states - "power from 1500 to 6500 rpm"
And a Lunati - 10230703 which states - "un-equaled power to 6200 RPM"
Lift: .494''/.513''

I have a somewhat stockish valve train with Mancini - "hardened" stock type rockers, chromoly push rods.

and a totally stock bottom end with known miles.

Trying to figure out how far I can push this thing before bad things happen.

Right now, I have a rev limiter set at 5,000 and it's been fine for about a year now, but with the RPM Heads and Cam maybe I can get away with more?

Thanks!

 

[R413]

Did you change the valve springs and go with what the cam needs? Do you know what valve springs you have? If you did change springs then take it to 6200 and see how it does.

It won’t hurt the bottom end, unless it’s worn out.

 

[RemCharger]

If it has the rpm springs on them, should be happy up to 6500. No more with the cast pistons.
I would think about a good (HV) pump as well.
Some may enjoy a LV pump, but not for me.

 

[R413]

Hv pump is not needed.

I wouldn’t like to be at 6500 with an unknown bottom end anyway.

 

[RJS]

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

 

[RJRENTON]

If it has the rpm springs on them, should be happy up to 6500. No more with the cast pistons.
I would think about a good (HV) pump as well.
Some may enjoy a LV pump, but not for me.

A HIGH VOLUME OIL PUMP is always a good idea, especially at higher RPMs because of the higher stresses imposed on the crankshaft and rod bearings. The hydrodynamic fluid wedge at higher RPMs will prevent (or lessen) the possibility of bearing failure. Just my opinion of course....
BOB RENTON

 

[dadsbee]

Hv pump is not needed.

I wouldn’t like to be at 6500 with an unknown bottom end anyway.

Exactly!

 

[Black_Sheep]

I have my rev limiter set for 6 grand (MP .509/292 cam)

I’ve buzzed it as high as 6200 on the chassis dyno but HP stops climbing around 5800 so it doesn’t make sense to go any higher…

 

[rumblefish360]

I have RPM Heads which states - "power from 1500 to 6500 rpm"

The first problem here is thinking the labeled rpm bracket of the part is the actual truth. It’s not!

And a Lunati - 10230703 which states - "un-equaled power to 6200 RPM"
Lift: .494''/.513''

Giving the duration @ .050 is far more helpful than anything you wrote down. The RPM range listed is fairly accurate.

I have a somewhat stockish valve train with Mancini - "hardened" stock type rockers, chromoly push rods.

Excellent

and a totally stock bottom end with known miles.

That “could” be a problem.

Trying to figure out how far I can push this thing before bad things happen.

I’d limit rpm to 6500.

Right now, I have a rev limiter set at 5,000

Way to low

and it's been fine for about a year now, but with the RPM Heads and Cam maybe I can get away with more?

A repeat answer, 6500. You run out of camshaft.

Thanks!

Best of luck and wishes to ya!!!
Enjoy it.

 

[496 polara]

Other variables such as exhaust,gear ratio,timing,and intake/carburetor may dictate the "usable" upper rpm limit.
RJS nailed it (IMO)for shifting at 5500 and see whether it is still pulling or leveling off.

Just a guess but if everything else is well matched I could see it liking a 5800 to maybe 6000 shift point. You won't know until you try it.

 

[BSB67]

The stock bottom end in good condition could go 6500. We just don’t know if yours is good.

If you have good oil pressure through the rpm range, you don’t need a HV oil pump. Arguably, if you don’t have good oil pressure, a HV pump is a bandaid and might be telling you the motor’s bottom end is not so good.

That cam should support a rpm shift point of about 6200 in your motor, if your induction system is adequate, and if the valve train and lifters maintain control.

 

[4mulas]

Maybe 5500. Stock rods are limiting factor. Avoid the cocaine zone

 

[RemCharger]

The first problem here is thinking the labeled rpm bracket of the part is the actual truth. It’s not!

100%

Giving the duration @ .050 is far more helpful than anything you wrote down. The RPM range listed is fairly accurate.

100%

Excellent

100%

That “could” be a problem.

100%

I’d limit rpm to 6500.

100%

Way to low

100%

A repeat answer, 6500. You run out of camshaft.

Best of luck and wishes to ya!!!
Enjoy it.

100%!!
Rumblefish gets 100% report card, based on knowing what he's talking about.

 

[RemCharger]

Maybe 5500. Stock rods are limiting factor. Avoid the cocaine zone

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.

 

[Curiousyellow71]

Depending on what shape the engine is I would say 5500-6000. Very likely there is no reason to shift above 6k on this old motor. 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+

 

[INTMD8]

Usually shifting a couple hundred rpm higher then power peak helps keep the car in its power band...unless the valvetrain is unstable.

Yes if valvetrain is stable a good starting point is 10% above peak hp rpm.

 

[BSB67]

That curve tells me a 6400 to 6500 shift.

 

[Curiousyellow71]

That curve tells me a 6400 to 6500 shift.

In a ideal world, but fast rate cams and hydraulic lifters usually run out of steam, that doesn't show on a computer sim.

 

[BSB67]

Of course hyd lifters can go 7,000. Whether you can buy them today for a BB Mopar and make them work is maybe another story.

but it doesn’t make a lot of sense to plan to shift a motor early because the lifter might not keep up.

Fast rate cams and crap lifters is a dilemma, especially for the 3.38” stroke BB Mopars

 

[Curiousyellow71]

Good point and driving the car should be pretty obvious as to whether you can get the rpms 10% past peak hp. Will it..?
One way to find out