3.23 or 3.55, this is the question

[adelmo]

I had 3.91 in my 69 Coronet RT with 29" tires but still buzzed to 3400 pm at 70.
Very happy with 3.23 now, still plenty of torque for burn outs and stays under 3,000 rpm highway speeds.

 

[dadsbee]

I love the 2.94's in the back of my Bee, the Cops in the late 70's certainly did not!

Then again I'm not interested in roasting tires off for shits and giggles... so I'd say 3.55/1 are what you're after, while 3.23's would certainly work.

 

[Curiousyellow71]

I have never regretted running 3.55s over 3.23 in anything for more performance. 3.55s are more fun tearing around and still go down the highway speeds good.

 

[1967coronet]

A decent condition well tuned RB should have no problem doing a off idle burn out with 2.94s and sure grip.
I run 3.23s in my 67 but did have a set of 2.94s in it a one time.
Like posted, tire dia plays a part along with a well tuned distributor and carb.

 

[RemCharger]

Pretty much have to agree, 2.54 was the best cruising high speed gear I've ever had and 456 was the best for ets , but I want one gear that will do both. Any links?

 

[AA1 68 R/T]

What distance are your long trips?

I vote for 3:55 or 3:91

I run 3:91 and a 3600 B&M stall in my 70 300 with a 440+6 with mopar 509 cam. Yes at 70 mph it’s up there in rpm on the highway but for burnout and a little fun off the light once in a while it’s awesome. I’ve driven the car up to 2-3 hours that way and the engine has help up for over 20 years lol
Good luck with whatever you choose.

 

[PROSTOCKTOM]

As far as the two gear set the OP asked about I'll say this. Going from a 2.94 that you're used to driving to a 3.55 is going to feel like you

need another gear. It all sounds good, but driving a 3.55 geared car without overdrive is absolute a borderline deal. If your 440 can't spin the

tires with ease using a 3.23 gear you probably need to look into what's wrong with the engine regardless of tire height.

Just install a couple windshield washer tanks in the trunk and squirt a little water on the tires when you want to really set the tires on fire.

No need to change the gears at all if you spray a little water on them and you'll still have your highway gear.


You can always build a Dana 61 if you want to have the Dana look under the rear and have the ability to run a taller gear set than the

tallest gear set (3.54) that a Dana 60 will offer. With the Dana 61 you can get a taller 3.07 and a 3.31. I have a Dana 61 in a car running the

3.31 and a pickup truck that has a factory installed 3.07 in it.


Tom

 

[Cojohnso1]

Is a taller gear necessarily best for highway use? Especially with automatic transmission?

I'm not sure cruising a couple hundred Rs under stall speed is ideal? Let alone the ideal RPM for a muscle car era engine build.

Yes, it will save some gas. But your engine may not necessarily agree with extended lower RPM use.

I'm sure there are some metric charts that reflect particular engine size/builds and ideal operating RPM levels?

 

[blue69runner]

Running 3.55 in my runner. Sometimes feel I need another gear. Just saying. But happy with it. Have a 489 chunk and thinking of putting in 3.23 gearing but not for sure. Have a A833 transmission Manual.

 

[Bighouse]

3:55 in mine. The car burns the tires when I stomp on it and it’s still “ok” going 60mph.

 

[Outlawd]

If your 440 can't spin the

tires with ease using a 3.23 gear you probably need to look into what's wrong with the engine regardless of tire height.

Yep, you got that right. I'm running 8 3/4 suregrip 3.23's and 295 tires in 3 cars, a stock 440, a blown 440, and a slightly modified 383. All 3 cars can do badass burnouts all day long plus drive down the 4-lane 70 mph at a decent rpm.

 

[AR67GTX]

I changed from 3.23 to 3.55 in my 67 GTX with stock 440 and TF. It made a notable difference in 1rst gear and I went from an open differential to a sure grip at the same time. It will light the tires and keep them spinning with relative ease. No doubt the other gears ranges are stronger too.

 

[Don Frelier]

I think a poll is in order here.

 

[Darter6]

Had a 64 Belvedere with 2.76. Switched to 3.55. Felt like I installed 5.13's
For me I have highway in every direction within 3 miles and speeds from 65 to posted 75.
Round here average drivers run 10 to 20 MPH faster. I went with 3.23.
Sounds for what you have planed and how you drive,my vote is 3.55

 

[Dave6T4]

The higher the gear number, the more it multiplies engine torque. Another option is to run a hard tire that spins easily, like a Michelin. Usually, the higher the expected mileage claim, the harder the tire is.
When I first put my 440-powered 1967 R/T together, I had Suregrip 3.91's in it on Michelin tires. It was a total squeal monster, unintentionally. I hated it and changed to 3.23's. It was like driving on marbles with the taller gears.

 

[Doorkicker]

You guys are friggin awesome!! Thank you for all the great comments!

Ok...

Tire is 275/60r15, so 28" dia. Old school.

I know I'm kinda wanting my cake and eat it too... I'll admit that It's gotta be something the mrs is ok with. And to top it off, it's not a high rpm engine.

I didn't consider the 3.91. i just had such a mixed experience with the 4.11 in my 76 fire chicken.

Man, you guys really have me thinking. The interesting part is i have three third members...741, 742 and a 489... Do you guys have more than one you swap out? Am i being stupid?

 

[Doorkicker]

The higher the gear number, the more it multiplies engine torque. Another option is to run a hard tire that spins easily, like a Michelin. Usually, the higher the expected mileage claim, the harder the tire is.
When I first put my 440-powered 1967 R/T together, I had Suregrip 3.91's in it on Michelin tires. It was a total squeal monster, unintentionally. I hated it and changed to 3.23's. It was like driving on marbles with the taller gears.

Lol! That's awesome. At least in my 17 year old brain in my 55 year old head

 

[Curiousyellow71]

If you want to really transform your car don't overlook installing a modern torque convertor. They can be made tight so the engine moves the car like its stock but when you nail it it flashes like a race convertor. A good company can build it custom for your car, 2.94s and a good stall can outperform 3.55s and a stock stall.

 

[Runcharger]

I don't generally recommend 3.55 but in your case I think they would work well for you. Going from 2.94 to 3.23 might not be enough of a change to make it worth while.

 

[hunt2elk]

I can pretty much gaureete that you won't like the 3.91's on the highway, even with 28" tires. I had that setup in my RR. Was a blast in town but screamed to much over 55 for my liking.