High RPM at relatively low speeds

mopar 3 B · Mar 22, 2020

I have 4:10's 275-15 not to many people go around that I don't want to at 60 mph it is only 3400 rpm and were it was designed to run. Gas mileage make no difference with higher gears as it still has to run in the proper rpm range. If I lived some where with am 80 mph speed limit the 3:23 gears would get installed.

33 IMP · Mar 22, 2020

Ceedawg said:
Making me think about mine before I get it all together. 4.1 Dana-4 speed-Hemi 775-14 tire. One car show is about 50 miles away, maybe I should use the 3.54s? Anybody know what rpm for either gear @60?

According to wallace calculators, assuming a 26.25" tire, 3.55 gear at 70mph is just under 3200, with a 4.10, just under 3700 at 70 mph. You can do your own calculations at Wallace Racing calculators. Marvelous resource! Freebie!

wyrmrider · Mar 22, 2020

creed lear to figure it out search
you could throw some tall skinny tires on for the trip
ran 4:11s in a283 vett- that was fun
440 is not a 283
but super trak pack cars were street driven all the time
get some ear pluga or noise cancelling headphones if headers and loud exhaust

Ceedawg · Mar 22, 2020

wyrmrider said:
creed lear to figure it out search
you could throw some tall skinny tires on for the trip
ran 4:11s in a283 vett- that was fun
440 is not a 283
but super trak pack cars were street driven all the time
get some ear pluga or noise cancelling headphones if headers and loud exhaust

I’m deaf so I just take out the hearning aids, silence, also radio delete. 500 rpm ain’t much between the two

mopar 3 B · Mar 22, 2020

wyrmrider said:
creed lear to figure it out search
you could throw some tall skinny tires on for the trip
ran 4:11s in a283 vett- that was fun
440 is not a 283
but super trak pack cars were street driven all the time
get some ear pluga or noise cancelling headphones if headers and loud exhaust

Yes and long before the stupid 55 mph speed limit and noise ordinances.

MoparLeo · Mar 22, 2020

http://www.wallaceracing.com/calcmph.php
Put this in your files for the future.

PRHeads · Mar 22, 2020

Fran Blacker said:
Had 4.10's 26.5" tire, 15 miles on the highway knew 4.10's were to much. Never mind 50 miles. Listening to your engine scream for mercy and getting passed by everybody. I was clogging the highway. Had 3.54's in before drove 400+ miles to see Niagara Falls and back to Rochester NY in one day for a NeHOA meet.

In 1968 my Dad bought an SS396/350HP Chevelle. 4 speed with factory 4.10’s.
That was the family car.

We lived in mid-town Manhattan and my Dad worked out in the suburbs in Elmsford.
Commuted every day with it.

We had a boat that was kept up in Cos Cob, Ct...... used to head up there and go boating many weekends in the summer.
In the winter, we’d go skiing in Vermont almost every weekend.
About 250 miles each way.

On the highway you were going along at close to 4K....... that’s just how it was.

He got rid of it with almost 70k on it...... still had the 4.10’s in it.

eldubb440 · Mar 22, 2020

isn't 4th gear input/output ratio supposed to be 1:1? you questioned the tranny in the original post......... put it in 4th with wheels up and turn the engine 1 revolution...... drive shaft should spin 1 revolution

Ceedawg · Mar 22, 2020

PRHeads said:
In 1968 my Dad bought an SS396/350HP Chevelle. 4 speed with factory 4.10’s.
That was the family car.

We lived in mid-town Manhattan and my Dad worked out in the suburbs in Elmsford.
Commuted every day with it.

We had a boat that was kept up in Cos Cob, Ct...... used to head up there and go boating many weekends in the summer.
In the winter, we’d go skiing in Vermont almost every weekend.
About 250 miles each way.

On the highway you were going along at close to 4K....... that’s just how it was.

He got rid of it with almost 70k on it...... still had the 4.10’s in it.

My Z28 would buzz 3000 @ 60 mph, never bothered me then either. Would run 80-90 on I95 (no radar back then except the little box cops set up)
Never knew what ratio it had, wife’s car.

High RPM at relatively low speeds

mopar 3 B

Well-Known Member

33 IMP

FBBO Gold Member

wyrmrider

Well-Known Member

Ceedawg

Well-Known Member

mopar 3 B

Well-Known Member

MoparLeo

NRA BENEFACTOR LEVEL LIFE MEMBER

PRHeads

Well-Known Member

eldubb440

more miracles than Jesus

Ceedawg

Well-Known Member

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