That is pretty spot on . I just built a 518 (46rh) and was lucky in that the trany looked like new inside . I still replaced all wear items and added some Sonnax parts and a Transgo shift kit .
Anybody running 276 gears?
- Thread starter hotrod swinger
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Where do you live ?
There is a reason that when Chrysler started using 2.76 or 2.45 gears in economy cars they also produced Torqueflites with substantially lower 1st gears and half that amount lower 2nd gears... When I installed the 42RH in my Dart I was surprised how much difference those lower trans gears made.
lemondana
BlackDart
I run 2.76's in everything I drive. My 71 Polara in my avatar, my surviver 67 Dart 270 and soon in my 69 Coronet R/T. I'm an old guy, I drive mostly on rural roads and interstates. To many people say highway driving. Highway and Interstate driving are two completely different things. To me, highway driving is 65 and Interstate here in Nebraska is 75-85. I don't much like being passed by econoboxes on the freeway. 3.23 gears on the interstate suck! I don't care if I can burn the tires or not. I'm not going to butcher any of my cars for an overdrive. 2.76 gears and as tall of tire that will fit. You guys that drive around in the city can run you 3.91's. Years ago, a friend had a nice Cuda, 440, 4 speed and 4.30 gears. He was always blowing-my Cuda this, my Cuda that. One extended weekend I drove my 69 R/T down to lower Missouri and Route 66. Total miles was around 1800 that weekend. When I came back, my buddy stated blowing about his Cuda again. I told him-I just got back from an 1800 mile drive and you drive your Cuda and run a tank of racing gas thru it in a couple hours. I asked-who do you think had more fun. I did! He never blew about his 4.30 geared Cuda again!
junkyardhero
Well-Known Member
i had both a 77 aspen and 87 dippy, the aspen had a super six and the dippy had a 360 with a TQ. in an impromptu stop light race the two were near dead even, that low gear 904 can be real beneficial in the right set up.
slantsixdan
=..=
That's not quite the right timeline. 2.76 rear gears became standard equipment in 6-cylinder and non-perf V8/automatic A-bodies for 1968. The wide-ratio gearset didn't come out til 1980, when 2.45 and 2.26(!) rear axles were being used in heavy cars with weak engines. 0-60 maybe sometime next month!
abodyjoe
Well-Known Member
after this road trip with 3.23 gears and a short tire I'm sticking a set. of 2.76 gears in it. i have a low gear set 904 and real good converter. i think it well be fine pep wise and I'll be anle to cruise 75 mph at a nice rpm.
i want a highway cruiser though. don't overlook the 2.94. its a great gear too.
I have 8 pumkins in my shop ( 2.76 /2.93/3.32/3.55/3.91/4.30) I chose to use the 2.76 because our speed limit is 80 mph and I drive it often . Got tired of turning 3600 rpm just to keep from getting run over . I guess my little 5.9 puts out some serious torque because I can roast my little Michelins with 2.76s…. The 46rh with 3.55s will give me best of both worlds .
But on a budget a gear change is more realistic . Anything from 2.76s - 3.23s will make your car more pleasant to drive daily .
But on a budget a gear change is more realistic . Anything from 2.76s - 3.23s will make your car more pleasant to drive daily .
I guess you have not bought any gears lately?
The price of gears and install kits are stupid high.
I just bought two sets, to re-gear a 4x4, it was way more than I expected.
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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I run 2.77s on the hiway, and I love it. But that's in overdrive,
Does that count, lol.
Looks like Sooke BC is elevation 200ft. Do a compression test.
Here's a rough guide, for a regular TF with a 2000 stall.
I made it up based on my experience. and it works for me.
For First gear take-off;
If your hi-perf 360 is making
190 psi, she'll pull any gear.
By 180, 2.76s are still doable
By 171, 2.94s are pushing it
By 163, 3.23s
by 155, 3.55s
by 147, 3.91s
by 140, 4.30s
The pressures are incrementally 5% difference.
The gears are nominally 9% between.
If you need to bias one way or another, that is acceptable.
If you are running your 3.55s with 155psi 360, you are at the limit, I would not run less gear, unless you are willing to sacrifice some seat of the pants on take-off. If you are exceptionally happy with your 3.55s well then try 3.23s, but do not trade away your 3.55s.
I also have a HO 360. Yes I could do with 3.23s, But I also have more than 180psi, a clutch, and a 3.09 low gear.
I would NOT run 3.23s with a 2.45 low and a stock-type 2000 or less stall.
But I would with a 3000 stall. Maybe even a good 2800, I love those.
Jus my opinions
BTW, once the car is off the line, and half revved out in first, a stout 360 will pull 3.23s real hard. Just get her up to 3500 and mash it!
junkyardhero
Well-Known Member
oh i have, make no mistake. i know that everything has gone up tremendously.
my point was more of the fact that it would be cheaper and easier to regear than to install an OD unit and all that entails. the middle ground of that, i guess, would be a low gear 904.
he's got an 8.75 so basically gear sets are like bread on a windowsill for him.
Re-gear is cheaper, no doubt.
Plus 8.75 never can have too many center sections with gear options.
I have 2.76 thru 5.xx gears to choose from depending on what I am building.
Plus 8.75 never can have too many center sections with gear options.
I have 2.76 thru 5.xx gears to choose from depending on what I am building.
BTW , whats your average interstate speed up there ?
Unless its 80+ 3.23s should be good compromise.
I should have asked that upfront .
Unless its 80+ 3.23s should be good compromise.
I should have asked that upfront .
ere
hotrod swinger
Well-Known Member
Our multilane highways are usually 100 km/hr.
I’d like to try 323 but then is it worth it to spend the money to go from 355 to 323.
I’d like to try 323 but then is it worth it to spend the money to go from 355 to 323.
Your gonna drop about 300 rpms on the highway
It is interesting how the 8 3/4" axle only went as tall as 2.76. One look inside will show how the taller gear, the bigger the pinion gear. The 2.76 pinion is a tight fit in there.
I've thought about the gears that the automakers used in these cars. Lots of GM cars has 2.56 and even 2.41 geared axles. Were there any gears taller than that? I don't know about Fords.
Our 8 1/4" axles had that 2.45 ratio. I thought that the 2.21 was also in the M body Diplomat/Gran Fury and Fifth Avenue cars but wasn't sure if they used 7 1/4" axles, 6 1/4" or both.
No reason to drop that far then .
3.23s will work great for you .
Down here in Idaho you will get passed at 85 mph often .
abodyjoe
Well-Known Member
here, play around with this calculator and get an idea what a gear change will do for you.
Speed/Tire/RPM calculator
our dart has a mild 360,low gearset 904, 9.5" converter,25.5" tire and a 3.23 gear. we just drove it 3000 miles. does well at 70 mph which the calculator says is about 3000 rpm. any more then that the mpg drops and while it will cruise at 85 mph it feels like you are pushing it. the car really likes 50-55 mph. runs nice and quiet and the MPG is about best there. with a 2.76 at the same 3000 rpm it should put me at about 82 mph. for me i know the car will still have plenty of pep around town for what i want. and even then i really only putt putt around town anyway and on the highway it will be a bit more comfortable in my opinion. but i know what i want from this car. I built the engine for what i want to do, i don't care about the track, its a pure street car that i want to drive anywhere i decide i may want to go.
again don't discount a 2.94 gear. depending on tire size that may be perfect for ya.
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Same in Arizona and Nevada. Speed limits are just a suggestion .Everybody is in a hurry.
In the 70's I would drive from Pittsburgh to Denver with a 70 4 speed Duster. Ruffly 1400 miles.
Pull the 3.91's out,install 2.94. Get to Denver and swap the 3.91's back in. 4 times a year.
As a teen thought nothing of doing the swap.
autopar3000
Well-Known Member
Yup, you nailed the maths. My recent OD install was about $3500 CDN , but I had some help so it's likely closer to $4500 CAD for the average guy. $4500 CAD = $3200 USD.
Here's how I came up with 85,000 km to make up the difference in fuel costs:
I went from 16 mpg with a 904 to 19 mpg with the lockup 46rh. These aren't guesses, I'm a bit obsessive about tracking fuel used and distance driven.
16 mpg = 14.70 litres / 100 km
19 mpg = 12.38 litres / 100 km
Therefore the difference is 2.32 fewer litres per 100 km.
Assuming a fuel price of $2 per litre (premium fuel in my area when I did the swap, it's about $1.80 now), and assuming an OD install cost of $4000.
That's a savings of $0.0464 per kilometer ($2 per liter x 2.32 fewer liters used per 100 km = $4.64 savings per 100 km. Therefore $0.0464 savings per 1 kilometer).
So if I wanted to save $4000 in gas, it's $4000 / $0.0464 savings per 1 kilometer = 86,207 km. Or 53,567 miles!
ir3333
Well-Known Member
lots of good info....but your cam, torque converter and tire size will determine your lo end torque.
a High performance 360 doesn't really tell the guys with experience enough.
a High performance 360 doesn't really tell the guys with experience enough.
abodyjoe
Well-Known Member
thats a long time... if i were to do OD it wouldn't be to save money, it would be to enjoy the car more..
hotrod swinger
Well-Known Member
I have a 2400 torque converter and 26.6 inch diameter tires and COMP Cams 20-670-4 233/240 Hydraulic Flat Cam
ir3333
Well-Known Member
I am no cam expert but that cam might not start making power until 3000 rpm. 2.76:1 rear gears may not be
the best fit with your stock converter. There are guys on the forum that can give you some direction.
the best fit with your stock converter. There are guys on the forum that can give you some direction.
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