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4 Speed vs. Rear end gear ratio

D

dcala84141

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Just curious if rear end (8.75 in my case) ratio has any effect in power shifting my 4speed trans. Back 50yrs. Ago I ran my 68 RR 4 speed at the drag strip more times than I could count I had 4:56 gears and I never and I mean never weather at the track or street missed a gear. Gas pedal to the floor through all 4 gears. Now 2020 50 yrs. later I now have another 68RR and I miss 3rd. consistently but now a have 3:23 gears. Maybe because I’m 70 now??
 
Maybe it's reflexes, maybe a worn synchro, or a worn/misadjusted shifter??? Probably not the gear ratio, if anything it probably helps cause the shifts don't come so quick.... Or maybe it messes with your rhythm.... Whatever the case keep trying till ya get it right...
 
If you have a Hurst Competition shifter you can shorten up the throw to 3rd.
 
70 years old and still out there banging gears? Heck yeah...That is an inspiration to us all!
 
Old habits die hard! Keep pounding gears!!

Trans Has 52 years of wear now. How is the shifter adjustment?

What kind of shifter and clutch did you have back then? And what kind now?

Now away from the car. We don’t know anything about you physically but doing some moderate weight training and exercise For a few months helps with coordination and muscle control. It just might help.
 
Last edited:
R413 said:
Old habits medieval hard!
Click to expand...

Uhhh, Auto-correct?

I recall reading that many manual trans cars were equipped with a numerically lower axle gear as standard compared to automatics.
I have a 3.55 in my Charger and am thinking of swapping in the 3.91s when I swap in the Tremec 5 speed transmission.
 
Last edited:
R413 said:
Old habits medieval hard! Keep pounding gears!!

Trans Has 52 years of wear now. How is the shifter adjustment?

What kind of shifter and clutch did you have back then? And what kind now?

Now away from the car. We don’t know anything about you physically but doing some moderate weight training and exercise For a few months helps with coordination and muscle control. It just might help.
Click to expand...
Not the same car back then I was running a hemi pressure plate and a zoom clutch disc stock 383 running consistent 12.7’s
Now I have stroke 383 to 450 , McLeod diapham pressure plate good to over 600hp.
Both cars had the stock hurst shifter ( the short one not the long pistol grip
I still hit 2nd no problem p.s. the car I have now is faster
 
Well...
RPMs climb much faster with the higher numerical rear gears, that certainly could make it easier.
Although I waited for my insurance policy (rev limiter) before I dared power shift (plant the gas and never lift, I DO use the clutch pedal) I cut about 1/2 second off my time, and previously had never shifted slowly when I did lift off the gas to shift. Now in my case, I'm sure keeping the vacuum operated outboard carbs on my 6bbl open has a LOT to do with the quicker times.
The first time I power shifted, dust came out from under the width of my dashboard :D The glove box door wasn't fully latched either..it became fully open.
I can't imagine not power shifting from now on, although I may want to lift once I get my 540 stroker under the hood, just so I don't go sideways hitting 2nd gear.
:steering:
My best friend complimented my improved shifting skills a few years ago, but I had only just started that day. I'm doing much better now.
 
dcala84141 said:
Just curious if rear end (8.75 in my case) ratio has any effect in power shifting my 4speed trans. Back 50yrs. Ago I ran my 68 RR 4 speed at the drag strip more times than I could count I had 4:56 gears and I never and I mean never weather at the track or street missed a gear. Gas pedal to the floor through all 4 gears. Now 2020 50 yrs. later I now have another 68RR and I miss 3rd. consistently but now a have 3:23 gears. Maybe because I’m 70 now??
Click to expand...
Good guess. :)
 
biomedtechguy said:
Well...
RPMs climb much faster with the higher numerical rear gears, that certainly could make it easier.
Although I waited for my insurance policy (rev limiter) before I dared power shift (plant the gas and never lift, I DO use the clutch pedal) I cut about 1/2 second off my time, and previously had never shifted slowly when I did lift off the gas to shift. Now in my case, I'm sure keeping the vacuum operated outboard carbs on my 6bbl open has a LOT to do with the quicker times.
The first time I power shifted, dust came out from under the width of my dashboard :D The glove box door wasn't fully latched either..it became fully open.
I can't imagine not power shifting from now on, although I may want to lift once I get my 540 stroker under the hood, just so I don't go sideways hitting 2nd gear.
:steering:
My best friend complimented my improved shifting skills a few years ago, but I had only just started that day. I'm doing much better now.
Click to expand...

Well I never tried lift and shift, Pedal to the floor and just kick the clutch pedal while shifting seemed so easy back in the day. Car was bought new in 68
Now different story
 
I USED to be able to shift my 383 4-speed 67 Satellite with the inland shifter as well as any of my friends with Hurst shifters. Back then we would go out and run our cars then go back and measure the distance between the 2-3 shift to try and see who was the better driver.
 
50 years ago I sucked shifting a 4 speed. Today, I still suck.
50 years ago I was told that (the guy riding with me) he could drink 2 cups of coffee between my power shifts..:(
 
What shifter handle and shifter? Some of them are really slow shifting compared to others. Also check to make sure the disc is releasing enough to create a .060-.100 air gap. I assume if you are missing the 2-3 that the 3-4 shift has not been tested? You might have a 3-4 shift fork going away on you. If you are going to power shift you need steel forks as itis only a matter of time before the bronze forks break. 3-4 being the most common.

Stay out of the rev limiter your timing chain will thank you. It it there for over rev protection, not because you need to shut the engine off to complete a clean shift.
 
Older now but I can still power shift just about anything but it takes seat time to become familiar with the chutch and shifter. I still make funny faces when I do LOL. Race face or something
 
It’s in the synchros/sleeves/and clutch. If the clutch does release or the sleeve/hub assy binds it won’t shift clean. Worn hubs and sleeves that have been filed to remove burrs and grooves shift very well. My Challenger (23spline, 3.55 gear, factory pistol grip) has the original (95k miles) components (slider and hub splines) that have been filed smooth. Run of the mill Centerforce clutch. Under accel you can push/pull on the stick as hard as you want. Full on the throttle. It won’t move until you touch the clutch. At that time it’s going in the next gear, now.
Doug
 
One thing I have found that may address your issue, and I have been driving big block 4 spd. Mopars for 45 years, is that if your seat is adjusted too far back, (which may be comfortable to drive) the reach to 3rd gear is just a bit too far, causing the odd mis-shift. I am 6'1" tall and my seat may appear to be too close to the steering wheel, but I don't miss the shift that way. Just an observation over the years, worth a try with no money down!
 
I agree with Doug you should be able to tap the clutch and just about throw the shift into third gear if everything is right. Sometimes a problem with the clutch disengaging correctly/completely on a full throttle shift won't show up until the higher gears in my experience.
 
I did notice that my clutch is engaging rather close to the floor. Instructions say to leave 1/8” gap between throw out bearing and the clutch fingers so I might have other issues. I might add my 1-2 shift is clean haven’t tried my 3-4 yet. I’m only doing less than 1/2 throttle to regain confidence. Yes I know about the seat thing my friend with a 68 RR hemi back in the day had trouble with the 2-3 shift moved seat forward and helped a lot
Next time I have car out I’m going to really put everything into that 2-3 shift maybe I was just lazy shifting that 2-3 shift
Stay tuned
 
Jeremiah said:
What shifter handle and shifter? Some of them are really slow shifting compared to others. Also check to make sure the disc is releasing enough to create a .060-.100 air gap. I assume if you are missing the 2-3 that the 3-4 shift has not been tested? You might have a 3-4 shift fork going away on you. If you are going to power shift you need steel forks as itis only a matter of time before the bronze forks break. 3-4 being the most common.

Stay out of the rev limiter your timing chain will thank you. It it there for over rev protection, not because you need to shut the engine off to complete a clean shift.
Click to expand...
Shifter is a hurst stock to the car later in 68 same as my car in 68 has the brown ball
I did not set my rev limiter my peak hp is at 5,700 rpm was thinking setting rev limiter at 6,500
H.P. Now is 550 at the crank
 
Jeremiah said:
What shifter handle and shifter? Some of them are really slow shifting compared to others. Also check to make sure the disc is releasing enough to create a .060-.100 air gap. I assume if you are missing the 2-3 that the 3-4 shift has not been tested? You might have a 3-4 shift fork going away on you. If you are going to power shift you need steel forks as itis only a matter of time before the bronze forks break. 3-4 being the most common.

Stay out of the rev limiter your timing chain will thank you. It it there for over rev protection, not because you need to shut the engine off to complete a clean shift.
Click to expand...
Shifter is a hurst stock to the car later in 68 same as my car in 68 has the brown ball
I did not set my rev limiter my peak hp is at 5,700 rpm was thinking setting rev limiter at 6,500
H.P. Now is 550 at the crank
 
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