Anybody running 276 gears?

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hotrod swinger

hotrod swinger

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For my 73 Swinger I have a high performance 360, 904 with stage 2 shift kit, and 8.75 with 355 gears. I was running 410 and switched to 355 which was a very nice change.

I drive this car "a lot" and I've been considering using an even higher gearset. Pretty sure I would like 323 but thinking more radical possibly.

Do you still get the seat of the pants thrill with a high performance engine and 276 gears?
 
hotrod swinger said:
Anybody running 276 gears?
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Not willingly. :p

I've never tried 2.76 gears in an A-body, but with the limited tire size it might not be as boring as it is in a B-body. 1980s M-body cop cars used 2.94:1 gears, which worked pretty well, but they also had the A998/A999 low (2.74:1) first gear. It's a direct swap into your A904, as I recall. A 2.76 axle combined with the 2.74 low first gear would give you about the same acceleration in first gear (only) as your current transmission would with 3.23s, but with a significant difference in freeway RPM. You could further recover some of the acceleration loss with a higher-stall converter, about which I know fairly little. All of my cars have clutch pedals.
 
hotrod swinger said:
For my 73 Swinger I have a high performance 360, 904 with stage 2 shift kit, and 8.75 with 355 gears. I was running 410 and switched to 355 which was a very nice change.

I drive this car "a lot" and I've been considering using an even higher gearset. Pretty sure I would like 323 but thinking more radical possibly.

Do you still get the seat of the pants thrill with a high performance engine and 276 gears?
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I got 2.xx:1 in my 68 Valliant not sure if its 2.94 or 2.76 on 26" tires with a 2800 stall and 380hp crate magnum.

It works ok around town (under 40) I usually don't shift into 3rd treat it more like an 2 speed with overdrive.

Still goes, burns rubber but is lacking I'm ok with it for now (last 7 years :) ) to get into the meat of the powerband got to get it up to 30-40 mph in first and hammer it, overall still fun but never had deep gears in it so don't really know what I'm missing.

More stall would help.
 
hotrod swinger said:
Sounds like a 2.xx gear won’t be great for cruising country roads at 40 mph.
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You can shift into 3rd no problem under 40 mph , but I like to keep the rpm's up to play around town.

So basically 2nd with 2.xx:1 acts like 3rd with 4.xx:1 around town.
 
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hotrod swinger said:
Sounds like a 2.xx gear won’t be great for cruising country roads at 40 mph.
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Like I said I use 3rd like an OD gear which is a cruising gear, should be fine on the back roads mine is.

Question is will the 1st gear performance satisfy you ?

What stall speed are you running ?
 
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273 said:
Like I said I use 3rd like an OD gear which is a cruising gear, should be fine on the back roads mine is.

Question is will the 1st gear performance satisfy you ?

What stall speed are you running ?
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Although a different set up, I run 3.23 with 29" tire in my big block Demon. I did run 2.94s for a while, was still nice to drive even at slow speeds, I just moved the 2.94s to my Charger for Bonneville. In a former life, I ran 2.73s in a big block Camaro. There it was still good thanks to big block power.
 
Also what size tires you running?

A tire basically has a gear ratio, = 24 divide by tire size.

29" = .83 and 26" = .92

29" (.83) with 3.23 = 2.68 final ratio
26" (.92) with 2.94 = 2.70 " " basically the same.

29" with 2.94 = 2.44 fairly big drop
 
2.76 is too far, especially with your engine. I run stock ish BB Mopars and I really like 2.94 for what you want to do. 2.76 just kills the torque and makes the converter slip way to much at low speeds. Think of a short wrench or a 14" long breaker bar on a lug nut.

I bought a car with 2.76 and a stall converter. I thought both would need to be swapped. Gears first, went from 2.76 to 3.23 and converter is just fine now, car moves at a lower rpm. Much different to the converter.

Think of a 10 speed bike. 10 gear is great for going fast. But jump on and try to start out and it doesn't want to go no matter how hard you pedal, now downshift and it's way easier to pedal. So same weight, same power, different gears.
 
with 2.76 you will have your foot in it off the line to make it move. There is no performance with 2.76 unless your trying to go from 50mph to 120mph lol, and you’ll probably need a slower timing curve etc. 3.23 would be best for street and highway
 
I am running 2.76s in my Barracuda right now . Engine is a stock crank and pistons 5.9 but have EQ heads , Oregon cams 222/229 545ish loft , headers and RPM intake. No issue with off the line and run around 3000 rpm at 80 .
I have a built 46rh to install this winter along with 3.55s.
If your engine has good low end torque it will make a great driver.
 
If it has a 2000+ stall converter, I'd reduce the slip at highway speed with a standard stall converter, so the loss is only about 5 mph compared to a locked converter or manual trans. Less heat too.
 
NoCar340 said:
A 2.76 axle combined with the 2.74 low first gear would give you about the same acceleration in first gear (only)
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And second gear, too.

Original Torqueflite ratios, first-second-third gears:
2:45, 1.45, 1.00

Wide-ratio Torqueflite ratios, first-second-third gears:
2.74, 1.54, 1.00

I put together a '65 with a healthy 225, 2.76 rear gears, and a wide-ratio gearset in the A904. I figured that would be a great combination. It wasn't; I hated it for a bunch of reasons, and from that I learned that the wide-ratio gearset, without an overdrive 4th gear, seems (to me) best suited for the vehicle configurations it was designed for: a weak engine and a tall rear axle in a heavy vehicle. Add an overdrive 4th gear (A500, A518…) and choose the rear axle in accord with that, and the picture changes.

When I went back to standard ratios in the trans and 2.94 or 3.23 rear gears in my '65, I wound up much happier. That is only one data point, however; others' experiences will differ with different engines and cars.
 
If you truly drive the car "a lot," overdrive is really the way to go.

I think you have to ask yourself: How much would it cost you to re-gear the diff? And how much would it cost to have an overdrive transmission installed? And what's the difference between those two numbers.

You will never make up the cost difference in fuel (I did the math, for me it would take about 85,000 km), but the driving experience is night and day with OD. The experience becomes more important when you're driving the car all the time, especially if you're cruising highways and country roads.
 
slantsixdan said:
And second gear, too.

Original Torqueflite ratios, first-second-third gears:
2:45, 1.45, 1.00

Wide-ratio Torqueflite ratios, first-second-third gears:
2.74, 1.54, 1.00

I put together a '65 with a healthy 225, 2.76 rear gears, and a wide-ratio gearset in the A904. I figured that would be a great combination. It wasn't; I hated it for a bunch of reasons, and from that I learned that the wide-ratio gearset, without an overdrive 4th gear, seems (to me) best suited for the vehicle configurations it was designed for: a weak engine and a tall rear axle in a heavy vehicle. Add an overdrive 4th gear (A500, A518…) and choose the rear axle in accord with that, and the picture changes.

When I went back to standard ratios in the trans and 2.94 or 3.23 rear gears in my '65, I wound up much happier. That is only one data point, however; others' experiences will differ with different engines and cars.
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I have to say I'm surprised to read that. I've not found a combination yet that doesn't improve with a lower first transmission gear. I hoard the early six-banger A833 3.09-first gearsets for just that reason.
 
Ran 2.76 in my 64 Slant Six. Never saw drive in the 1/4 mile.
Went thru the lights in 2nd . Still had fun.
I run 2.76 in my 63 Belvedere, 70 mph@ 2500 rpm.

IMG_4815.JPG
 
at least you have a 8.75 so switching ratios is "easy"...

i've always considered 3.23 to be the compromise, relatively easy on cruising RPM and easily adjusted up or down with reasonable tire sizes that are widely available and don't look like truck tires; but with enough punch to get you up and out of the hole.

a 2.9x or there abouts would make a great road gear if you have the torque to pull it both on the highway and around town.

anything sub 3.55 would benefit from a low gear set, imho. and while having some stall is always good, that lower gear might allow you to get away with stock stall.
 
autopar3000 said:
If you truly drive the car "a lot," overdrive is really the way to go.

I think you have to ask yourself: How much would it cost you to re-gear the diff? And how much would it cost to have an overdrive transmission installed? And what's the difference between those two numbers.

You will never make up the cost difference in fuel (I did the math, for me it would take about 85,000 km), but the driving experience is night and day with OD. The experience becomes more important when you're driving the car all the time, especially if you're cruising highways and country roads.
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here's some quick maths:

518: $600 (CL/offer up)
comprehensive rebuild kit w/ shift improver & upgrades: 800
torque converter: 400~1200 (so let's split the baby and call it 800)
mount: 400
lock up/OD control kit: 150
yoke if you didn't get one: 50~100
shortening drive shaft: 150
trans cooler kit: 100
misc odds and ends such as fluid, biscuit mount, dipstick, wiring supplies, etx: 200

so you're in 3200~3500 easy money

this surmises that A: all the hard parts in the trans are good and you're not upgrading planetary gears, and B: you're doing all the work yourself, as well as C: you're okay with cutting up the car.

the OD option has all the pros of not spinning the motor to the moon at highway speed and getting *slightly* better fuel mileage which would only be important if you were long hauling it, tbh. but suffers all the cons of spending a grip of dough, a bunch of time and cutting up the car.

vs spending $500 for some gears and saying: ehhh, that's good enough.
 
hotrod swinger said:
2200
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I imagine you want to go 2.76 for highway reasons ? First off do you need to in the first place what rpm be acceptable ? And what gear do you need to get there ? I wouldn't go any higher than necessarily.

I'd drive at the speed where I find the rpm acceptable, take note of that rpm and calculate the gear needed to drive at that rpm but at the speed I want to cruise at, don't forget to add some slippage rpm.

If your not too far off you could bigger tires might get you there or help dial you in.

If performance is still important to you OD would be the way to go. But another solution is get a 904 with deeper gears and lockup converter. Lockup gonna drop a few hundred rpms allowing keeping deeper rear gear plus has deeper 1 & 2 making the rear gear act deeper in those 2 gears. Could also get a 2800-3200 stall to help off the line/light.

Now you don't have to do it all at once, could pick the rear gear and tire that gives you perfered rpm without the slip calculated in so it be a few rpms higher then get the tranny with a stall/lockup deeper gears ready and swap it in down the road.

Still be able to cruise while keeping as much performance as you can without going OD.
 
I am, behind a 340 and a 727 and I love it.

When I was running a 4 speed with a 245/60/14 tire you would have to ride the clutch a bit to get it going, but behind the 727, no problem.

The downshift from 3rd to 1st in the auto is still pretty impressive but not neck braking.
 
junkyardhero said:
at least you have a 8.75 so switching ratios is "easy"...

i've always considered 3.23 to be the compromise, relatively easy on cruising RPM and easily adjusted up or down with reasonable tire sizes that are widely available and don't look like truck tires; but with enough punch to get you up and out of the hole.

a 2.9x or there abouts would make a great road gear if you have the torque to pull it both on the highway and around town.

anything sub 3.55 would benefit from a low gear set, imho. and while having some stall is always good, that lower gear might allow you to get away with stock stall.
Click to expand...
To expand on this. I have a 2.94, 3.23 and 3.91 center sections. It takes about an hour once you change them often enough. I have been known to change from 3.91 to 3.23 just for the long drive to MITP - about 5hrs away - then back to 3.91 the next week.
 
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