3.91 or 4.10 on street???

[1971scamp383]

hi all....i was wondering if i should go with 4.10 or stick with my 3.91 gear....?? i have 29 inch tall rear tires... i mostly drive the car on the streets...sometimes but rarely on the road(just to go to the dragstrip..about 35 min of my home on a 55 mph speed limit road) my car is pretty heavy(4200) and i want the car to launch good!!!

[wedgie]

I use a 4.10 with 28" tires and a 3800 convertor behind my big block stroker. Car weighs just over 3700#. A ball to drive on the street but very uncomfortable at 60MPH cruising.

[Capt Jack]

not a huge difference between the two I would think.  Im on 4.10s now in the duster.  I keep thinking its actually too much gear for my combo. personally for me 3.73's or 3.55's will likely be in the next setup

in your case, Id just stick with the 3.91's since theyre already in place.  if you were doing more drags than roads I might say 4.10s

[moparhunter]

thats not street gears! I used to Run 5:13 on the street in my Dart with the 360 , It was brutal out of the hole!! 3100 Rpms at 30 mph !!!

[IL.DART340- 4SP]

not a huge difference between the two I would think.  Im on 4.10s now in the duster.  I keep thinking its actually too much gear for my combo. personally for me 3.73's or 3.55's will likely be in the next setup

in your case, Id just stick with the 3.91's since theyre already in place.  if you were doing more drags than roads I might say 4.10s

I will be useing 3.73 in my street car. But like mention why spend the money and time you have a good gear already. Just my two cents worth.

[austinbbmopar]

Im happy w/ my 3.91s... Just cause i love to drive my car and not be scared of 80mph!

[guzzimike]

3.91

[68_Val_Sedan]

my chrysler 300 weighs 4200 with  me in it ... and i have 3.73 with 31" tires ... and am going to put a set of 4.30 in it ... the car will probably never see the track just need more gear to get the weight moving

[kudah440]

Ive got 3.91s in mine too... For what its worth Im pulling them to put in 3.55s.  Not fun when youre cruising at 75 mph to get anywhere. Great gear, but getting to be annoying.

[75Dart440]

I have a 3.91 with 26.5 inch tires.  Wouldn't want to interstate drive it much with that combo, but I put them in knowing I would later go to a 28 or 29" tall tire.  Hits about 2800 or so at 55mph.

[Prodart]

4.10s but i don't do a lot of drives over 1 hour away. I'm running 4.56s so that would be as high as i would step up.
My .02

[illfish]

3.55

[NYrr496]

I have 355's from my Charger going into my roadrunner. I was going to swap to 391's, but the gain wasn't enough to justify the expense. You're in the same boat. Stick with the 391's.

[moparrr07]

its an 8 3/4 so that means easy gear swaps, i will be running a 3.55 sure grip in one case and then swap out a 4.56 spool for the strip, best of both worlds, 30 min to swap

but to answer you question, it wont make that much difference, go with the better deal

[Capt Jack]

my chrysler 300 weighs 4200 with  me in it ... and i have 3.73 with 31" tires ... and am going to put a set of 4.30 in it ... the car will probably never see the track just need more gear to get the weight moving

personal opinion...I had a  and stuck 4.30's in my old GTX daily driver....


hated....H A T E D  it.   then again it was probably due in part to the smoking POS bomber 440 I had in it just wouldnt rev/pull those hard enough to really work well.
purely my humble opinion, though

[CudaSRT8]

You would hardly notice any difference on the strip between 3.91s and 4.10s.   "Back in the day", the Dana equivalent to the Mopar 3.91 rear was the 4.10.   Virtually the same result.   IF you want to step up for the strip, go with a set of 4.30s.   Wouldn't be too bad on the street, but you wouldn't like them on the highway.

Maybe you could lighten up the car a few hundred pounds?   

[chryco]

3.91`s in my Bee' 4spd. Just fine.

[Bakaruda]

I did 3:91 with overdrive.

[austinbbmopar]

yea... overdrive... that sounds nice! haha would drive like my Dakota R/T then! Which is awesome by the way!

[Ace]

I had 4.30's in my last small block car that I drove to work 25 miles each way.  Wasn't too bad, I think with a 28" tall tire at 65 I was turning 3800R's or something like that with a C4 auto (3 speed)

[dangerdawg]

i really like my 391's

[ksdartguy]

Not enough diff to bother changing, unless you have enough rpm range to buzz the motor,
and you just need a little more.

[therocks]

 I have 391s in the 65 the kid has 410s in his 62 300.Not much differebce.Mine is 4 speed.The kid drives his all over and still gets decent mileage. Ill probally put 456 or 488s back in mine as its mostly short driven.Just ticks me off that I sold my 88s back in the 80s for 150 complete with SG.I still have to go Dana as I know the 8 3/4 will probally break at my power level.Rocky

[67Dart383]

what length track you run at if its a 1/8, then use the 4:10, we run 4:30 and not much good on the street , but a mofo at track and just rite for the 1/4

[Crazy73]

I have 4.10s with a 26" tire in my 340 Dart and wish I had gone with 3.55s - I like to take some long drives in the summer but 60mph highway jaunts at 3600rpm is no fun - especially because I'd rather cruise at 65-70.  I see 3.55s in the future for the Dart...

My '68  383 b'cuda has 3.23s in it and those will either be staying after I see how it drives, or it will get 3.55s also.

[jyrki]

My experiences are from lighter cars, but in a dual purpose vehicle, I really like the higher stall speed/longer rear gears combo better than lower stall/shorter gear. My last combo in a 3570 lbs car was 3.23 gears, 28" tires and 9.5" converter that gave about 4500 rpm stall. This was a custom PTC unit, that cost about 450$. It pulled tight below the stall speed in regular traffic, but let the rpms rise when needed. On the highway, at 65 mph I had about 2500-2700 rpm. A deep oil pan and an external trans cooler kept the oil temp acceptable. The car run 10.5 at the strip, was driveable everywhere, and had almost 180 mph top speed. In a heavier car, the converter tends to slip more, since more torque is neede for a certain acceleration, but still I prefer it over a short gear lower stall combo, since it's usually a quicker compromise at the strip. There is about 5% difference between 3.91's and 4.10's; that is a pretty small difference and easily compensated with a tire height change, if desired.