3:91 vs 3:55 - Opinions please

[sadil340]

I have a 3:55 SureGrip in my 340 four speed Cuda and am considering going with a 3:91. The extra snap will be fun but I want to make sure it won't wind too high on the highway. I'm also wondering if it's a major hit to gas mileage but truthfully the extra performance is worth more than a mile per gallon or two as far as I'm concerned.

Anyone make this switch? What's your experience? Thanks!

[73Chally]

I had the choice between 3.55 and 3.91 last year, and went with the 3.91.  I don't drive it on the highway enough for that to be a concern to me.  I have no idea about mileage, but the extra snap is more than worht any loss.  If highway driving and mileage are a concern, I would probably go with a 3.23, but if not then I would go with the 3.91.

[GoodysGotaCuda]

When i didn't drive highway when i put the 3.91s in. Was very happy with them. I now drive a good amount of highway wherever i go, little indifferent on the 3.91s. I'm about 3400rpm for 67mph or so..so it's winding pretty well at a decent cruising speed. It will twist up really well to 100+ when you nail it

Really does depend on how much highway driving you do

[nivvy]

I have a 3:55 SureGrip in my 340 four speed Cuda and am considering going with a 3:91. The extra snap will be fun but I want to make sure it won't wind too high on the highway. I'm also wondering if it's a major hit to gas mileage but truthfully the extra performance is worth more than a mile per gallon or two as far as I'm concerned.

Anyone make this switch? What's your experience? Thanks!

i run 3.91's with a 28" tire and im about 3100rpm at 60+ish ... 3.91's is the bet overall gear made.... 

[bb71challenger]

If you have the money or come across a good deal I would get 2 different chunks. I currently have a 2.94 sure grip in my Challenger so when I go to setup my fun gears then the sky's the limit. I am thinking about 4.30 or 4.56. I have a set of 5.13's but they are too low and howl like a werewolf anyway.

[vinb]

Good idea to have two complete center sections.
I have a complete 3.23 open and a 3.55 suregrip, also a 3.91 gear set...

[Moparal]

Good idea to have two complete center sections.
I have a complete 3.23 open and a 3.55 suregrip, also a 3.91 gear set...

   I have 276,294,323,355,391,410, and 456 etras. I had just decided to sell off a few of them last night since I am going to dana now

[drewcrane]

it seems we are all in agreement, 3:55 are good all around ,3:91,s WAKE THE CAR UP , THERE IS MORE TORQUE AVALABLE! ,its a huge difference to me,yes 3:91

[71chally416]

The last SB car I switched gears in knocked .01 off the ET (with 9" slicks) going from 3:55's to 4:30's. I would expect half of that or .005 at best.

[Moparal]

   I believe your decimal point is off.

[nivvy]

  I believe your decimal point is off.

 

[IMNCARN82]

I love the 3:91's for all around street.Couldn't drive on the freeway too good.Now the 5 speed makes that possible too.I didn't want to give up the 3:91's at the stoplights...It helped me. I love 'em!!

[inot2old]

Like other people said, it depends on what you use your car for.  If you travel on the highway much, keep the 3:55.   I ususally have to drive 30 miles or more to car shows & my 4:10 gears suck on the highway!

[71chally416]

  I believe your decimal point is off.

You are correct. .05 (5 hundreths) assuming the car even hooks up. The point is it won't matter at all in a street car with a 4 speed. It'll just wind the motor tighter while cruising and use more gas.

[Carlwalski]

I have 3.91s but have OD so run like 3.05. I cruise the highways a lot 50/50 driving for me, I'd give your engine a little less rotational strain and go for 3.55s. .55s will still offer a great launch. Hoe much highway driving DO you do?