Theoretical top end of a second generation Charger

[smegslebchef]

What kind of top end is a 440 or 426 engined 1968 to 1970 Charger capable of with theoretical gearing? I see speeds generally falling in between 110 to 135 MPH for the 440 and 426 cars when I look on the internet. I know a lot of the cars had different ratios and I think many had their top end limited by running out of gears because they were meant for getting off the line well instead, and only the 500 and Daytona were designed with top speed in mind.

[green69rt]

If you go by the speedo, my old 440 topped out at 155 after a long run,  in reality it was more likely around 135 or 140(if that). 323gear with TF. Doing anything over 120 MPH with the bias belted tires at the time was suicidal.

[mr. hemi]

My '69 Hemi Charger will pill 6200 rpm in 4th, with a 3.54 Dana. Never looked at the speedo, they are inaccurate anyway. Have to do the math for a 27" tall tire.

[Homerr]

Here are a couple calculators.

27" tire, 6200 rpm, 1:1 trans ratio -

3.54 = 140.75mph
3.23 = 154.25 mph

http://www.csgnetwork.com/speedcalc.html

https://spicerparts.com/calc/transratio/index.html

[cp-chargr/6]

As you said, it will have to do with the gearing of the car, and how far is the safe max RPM for the engine, and tire size. In Nascar they changed gears, tire sizes, modified engines to rev faster, etc.

If you check:

https://www.automobile-catalog.com/car/1969/634295/dodge_charger_rt_440_v-8_magnum_torqueflite.html

or: https://www.automobile-catalog.com/car/1969/634310/dodge_charger_rt_426_v-8_hemi_4-speed.html

It brings you to the 130-137 MPH. They took the time to do the theoretical calculations, I assume with the standard differentials (3.54 in the hemi)

MOPAR was going to sell you a car for enjoy, not to reach 200 MPH, when the speed limit was what? 70?. Better get to 70 quickly  

[70 sublime]

My car with a 383 auto and 292 gears in the back gets to 120 and seems to just stop gaining speed as in the motor has no more push left in it to go any faster
We have some of those radar speed signs around and when I am doing 50 the sign says the same thing so I think my speedometer is about right

[John_Kunkel]

In 1969 the CHP achieved 140 mph in a Polara measured with a fifth wheel. 440 Magnum and 3.23 gears and fairly large tires.

Wind resistance often trumps math calculations.

[Mike DC]

   
The aero limitations aren't just about drag coefficients.  At well over 100 mph there is so much air getting rammed under the front end that the handling is getting scary.   The tunnel-back rear window is pulling weight off the rear tires.  Etc. 

These cars just weren't made for high speeds.  In the 1960s a Detroit car company would have dozens of bodywork stylists on the staff and not a single aerodynamic engineer.  It wasn't part of the conversation.  The styling department didn't even understand the basic principles.   

[oldgold69]

 I back in the day thought I would see if I could peg the speedometer. Got on a long straight stretch. Massed the gas and let her go  I had been up to 120 lots of times. Hit that and kept on going at about 140. The front end started to get real light. The car started to wander a little. Then the windshield wipers went from park to fully extended.  That's when I took that as a sign. It felt like the air was screaming under the car.

[Kern Dog]

I went 130 with my first 440, a 727 and 3.55 gears. It felt fine to me. I have a nose down rake and stiff suspension though.

[Slowpoke]

in my 68 RT with a built 413 and 727 with stock gears 130 was top end.
This was on a paved banked track back in 1981.
a lot of lift and lack of fuel delivery prevented any more speed.

[cdr]

I have been 140 in my junk & it was stable & smooth, the Aero problems dont start until over 160 mph

[Mike DC]

I have been 140 in my junk & it was stable & smooth, the Aero problems dont start until over 160 mph

140 on the street?  That's pretty damn fast. 

IMO dragstrips don't bring out aero handling problems as much as real highways.  The suspension doesn't flex as much because it's smoother.  No turns.  There are usually enough surrounding obstacles/terrain to reduce some of the crosswinds (compared to a highway in rural Kansas).   

[cdr]

I have been 140 in my junk & it was stable & smooth, the Aero problems dont start until over 160 mph

140 on the street?  That's pretty damn fast.  

IMO dragstrips don't bring out aero handling problems as much as real highways.  The suspension doesn't flex as much because it's smoother.  No turns.  There are usually enough surrounding obstacles/terrain to reduce some of the crosswinds (compared to a highway in rural Kansas).    

My car is a street car Daily driver , it had a 3.54 gear it now has a 4.10, it would still be no problem & it DID & still does have an overdrive a518, 140 mph is a cake walk in my car. just drove almost 100 miles today out in the country

[Challenger340]

I think actual tire diameter is the limiting factor to top mph with the factory 14" Rims and 3.23 cogs ? ..... power is NOT the problem even on the factory stock 440 Magnums in my experience, as I've scared the shit 'outa myself more than once !

I went with a set of P225 70R 14's..... mounted them... inflated them to 60 psi and set them out in the sun for 3 days turning occasionally, wherein by my Calcs I was able to "stretch" them, albeit only slightly to just a hair under 27" diameter if even that ?

All I know is the old thing will climb to 125-130 mph on the speedo pretty quick and with ease.... and still increasing far past what is safe IMO for the suspension or the Engine oil supply over any sustained periods ! I just wouldn't want to hurt anything in the Engine ? (and I'm pretty anal about making sure the other safety things are kept up to snuff on the Car.)
Just say'in.....
I'm too scared to see what it would go to ?     But the "passing" characteristic from 65-70 mph to well over 100 mph is impressive !

[cdr]

I think actual tire diameter is the limiting factor to top mph with the factory 14" Rims and 3.23 cogs ? ..... power is NOT the problem even on the factory stock 440 Magnums in my experience, as I've scared the shit 'outa myself more than once !

I went with a set of P225 70R 14's..... mounted them... inflated them to 60 psi and set them out in the sun for 3 days turning occasionally, wherein by my Calcs I was able to "stretch" them, albeit only slightly to just a hair under 27" diameter if even that ?

All I know is the old thing will climb to 125-130 mph on the speedo pretty quick and with ease.... and still increasing far past what is safe IMO for the suspension or the Engine oil supply over any sustained periods ! I just wouldn't want to hurt anything in the Engine ? (and I'm pretty anal about making sure the other safety things are kept up to snuff on the Car.)
Just say'in.....
I'm too scared to see what it would go to ?     But the "passing" characteristic from 65-70 mph to well over 100 mph is impressive !

Bob your Charger is on the top of my list of favorite Chargers, awesome car !!!

[v21hemicharger]

At the front straight at Thunderhill, I just get into GV overdrive for maybe 2 seconds and am at 155 Via GPS before braking.  Don't have time to look at RPM's.  I could see myself 165-170 if longer.  Hotchkis suspension 512 ci A-833 Gv overdrive 4.10 Dana 295/50/18.

[Kern Dog]

No offense but I'm not buying that. 4.10 gears into a Gear Vendors is a 3.20 final drive, You're not going to make 170 mph without spinning 2 stroke like rpms.

[cdr]

No offense but I'm not buying that. 4.10 gears into a Gear Vendors is a 3.20 final drive, You're not going to make 170 mph without spinning 2 stroke like rpms.

only 6800 rpm with 5% converter slip no big deal for a 512 with the correct parts

[c00nhunterjoe]

No offense but I'm not buying that. 4.10 gears into a Gear Vendors is a 3.20 final drive, You're not going to make 170 mph without spinning 2 stroke like rpms.

I trap 7200 in my 440. Aint a big deal.

[v21hemicharger]

Dog that thing sees 7000 every day of its life. And tires are 295/45's not 50

[c00nhunterjoe]

Wasnt even thinking about the plymouth. 4.10s behind the 572 on a 32x13.5x15. 1/4 mile 9.90@ 160 on a throttle stop.

[Kern Dog]

That is impressive.   

[John_Kunkel]

No offense but I'm not buying that. 4.10 gears into a Gear Vendors is a 3.20 final drive, You're not going to make 170 mph without spinning 2 stroke like rpms.

At first, I thought the same thing but look at his tire size...almost 30" in diameter not counting growth at speed.

[Homerr]

At the front straight at Thunderhill, I just get into GV overdrive for maybe 2 seconds and am at 155 Via GPS before braking.  Don't have time to look at RPM's.  I could see myself 165-170 if longer.  Hotchkis suspension 512 ci A-833 Gv overdrive 4.10 Dana 295/50/18.

Do you have any videos of you racing your car?   

[Kern Dog]

Spinning a 4.250 stroke engine to over 7000 rpms sounds risky!

[c00nhunterjoe]

Spinning a 4.250 stroke engine to over 7000 rpms sounds risky!

Mine is 4.5 for the record. Been doing it for years.
7400 here
https://youtu.be/2ciFpx9QaxQ

[Challenger340]

Spinning a 4.250 stroke engine to over 7000 rpms sounds risky!

As long as the Engine can still make power and is still pulling against the "load" things typically don't fly apart ?

It's when people spin them that high when they are well past their powerband and peak power that things begin to 'freewheel'.... just rev'ing higher and higher with little pull remaining against the "load".... wherein stuff can exit stage BOTTOM !
Just say'in....
if your peak power occurs at 5,500 rpm and you keep spinning it to shift at 7,000rpm ? The engine is so far down the backside of it's power curve the parts are basically 'freewheeling' = scatter risk !
That said....
if you are running 280+ degree's at .050 Camshaft with Heads that can breath/still deliver Flow up there... then typically NOT a problem !

I have street pump gas 572 Hemi's using KB Blocks and Stage V Heads out there making 950 hp that see 7,000+ rpm shift points regularly.... year after year after year

[INTMD8]

At the front straight at Thunderhill, I just get into GV overdrive for maybe 2 seconds and am at 155 Via GPS before braking.  Don't have time to look at RPM's.  I could see myself 165-170 if longer.  Hotchkis suspension 512 ci A-833 Gv overdrive 4.10 Dana 295/50/18.

Awesome 

[cp-chargr/6]

As Challenger340 mentions, a modified engine surely can rev faster than a factory one made. Why: diff cam, larger carb, higher displacement (overboring) and compression, lighter pistons, rotating assembly balancing, no emission stuff, etc. can provide you with torque at higher RPM than the nominal limit of the engine as per factory specs... Also, as mentioned before tire diameter matter as much as differential gear ratio.

The theoretical limits are taken at factory production conditions. After that, of course there are ways to get higher top speed! (including driver's ... abilities, let's keep this civilized...).

[v21hemicharger]

At the front straight at Thunderhill, I just get into GV overdrive for maybe 2 seconds and am at 155 Via GPS before braking.  Don't have time to look at RPM's.  I could see myself 165-170 if longer.  Hotchkis suspension 512 ci A-833 Gv overdrive 4.10 Dana 295/50/18.

Do you have any videos of you racing your car?  

Here's an old one with the 440 engine before the 512 and gv was added

https://www.youtube.com/watch?v=2MHwDbGwSkQ

[Kern Dog]

I remember seeing you and the car at the 2011 Spring Fling.

[GT]

At the front straight at Thunderhill, I just get into GV overdrive for maybe 2 seconds and am at 155 Via GPS before braking.  Don't have time to look at RPM's.  I could see myself 165-170 if longer.  Hotchkis suspension 512 ci A-833 Gv overdrive 4.10 Dana 295/50/18.

Oh man your charger is tough looking - very nice pic in front of the chevy

[BSB67]

No offense but I'm not buying that. 4.10 gears into a Gear Vendors is a 3.20 final drive, You're not going to make 170 mph without spinning 2 stroke like rpms.

I trap 7200 in my 440. Aint a big deal.

No. But seems pretty far from the spirit of the original post, don't ya think?

[c00nhunterjoe]

No offense but I'm not buying that. 4.10 gears into a Gear Vendors is a 3.20 final drive, You're not going to make 170 mph without spinning 2 stroke like rpms.

I trap 7200 in my 440. Aint a big deal.

No. But seems pretty far from the spirit of the original post, don't ya think?

Not really. "Theoretical top speed of a charger". I am running a 727 behind a 440 in a charger. How is that off the path when the question was asked about high rpm?

[cp-chargr/6]

Well, you might be right. OP talked about Top Speed with "theoretical gearing", not anything else. He said also that thought that street cars (with "theoretical gearings") were designed more to start quickly than for high speeds (i.e. the Daytona...). I think that the essence of the discussion is that besides "theoretical gears", if you change tire size and get sure your engine can spin faster than factory recommended (in your case 7000 RPM, when factory tic-toc-tach was red lined at 5000 RPM, with factory max torque around 4300-4600) you will go faster, even with "theoretical gear". In fact I found some discussion about 5000 RPM being pretty conservative even for stock conditions (but I guess safer for MOPAR from the warranty side).

I also don't know how modified is your engine c00nhunterjoe, what have you done to your 440?

[RiverRaider]

Not theoretical but actual, one of the Car Life magazine tests for a Hemi 69 500 with 4 spd. on F70 15 tires had top speed at 134 @6100 also ran 13.68 in the quarter.  No information in rear end ratio.
I recall reading articles for 142 mph and 147 mph runs the latter was a salt flats run in a Hemi Daytona but I could not find hard copy to back up my memory.

[hemigeno]

No information in rear end ratio.

The ratio would have been 3.54:1 (Dana 60), as 4.10's would not have produced top-end speed #s.

[c00nhunterjoe]

Well, you might be right. OP talked about Top Speed with "theoretical gearing", not anything else. He said also that thought that street cars (with "theoretical gearings") were designed more to start quickly than for high speeds (i.e. the Daytona...). I think that the essence of the discussion is that besides "theoretical gears", if you change tire size and get sure your engine can spin faster than factory recommended (in your case 7000 RPM, when factory tic-toc-tach was red lined at 5000 RPM, with factory max torque around 4300-4600) you will go faster, even with "theoretical gear". In fact I found some discussion about 5000 RPM being pretty conservative even for stock conditions (but I guess safer for MOPAR from the warranty side).

I also don't know how modified is your engine c00nhunterjoe, what have you done to your 440?

The daytona in 1969 broke 200 mph so take that for what its worth. In my case, not as modified as you may think. My 440 is a stock hemi crank, pump gas pistons, indy 440-1 heads and a big solid roller cam. It wants rpm. Its pulling hard still when it traps. I choose to not spin it higher. No dyno sheets so no clue where it will peak.

[c00nhunterjoe]

Double post

[HPP]

I went with a set of P225 70R 14's..... mounted them... inflated them to 60 psi and set them out in the sun for 3 days turning occasionally, wherein by my Calcs I was able to "stretch" them, albeit only slightly to just a hair under 27" diameter if even that ?

At first, I thought the same thing but look at his tire size...almost 30" in diameter not counting growth at speed.

Bias ply tires could be stretched by using the trick in the first post. However, I've found that street radials do not respond similarly to this trick, nor do they grow in height at speed either. 

[sccachallenger]

OK, not a Charger, but thought this might be useful.
1972 340 Challenger, 4 speed, 3.23, g6015 bias belted T/As.
I was young and dumb then, wanted to know what top speed was.
Engine was stock, with headers, wouldn't go past 5500 rpms with stock fuel pump in high gear.
Memory a little fuzzy, but think speedo showed 128.
Added a Holley red pump, easily hit 6000 RPMs when I lifted, speedo showed 135mph.
On at least two occasions in my own cars, the stock mechanical pump was the limiting factor.
Unless I added one of the "race" mechanical, or an electrical pump no way could the car pull strongly in top gear.
Of course your results may vary.