Torqueflite 727 with 3.91 rear end

[vso737]

Is anyone driving a 1969 RR with a 727 automatic and with a rear end ratio of 3.91 ??

If so, any positive or negative comments about how the car handles.

Thanks,
Mike

 

[5.7 hemi]

My dad has a 70' Challenger RT, 505, 727 and 3:91's. That car is wicked fast and if ya look at "go pedal" wrong, it will light the tires and get out of control real fast. So now he wants me to build him another "489" case with the crush sleeve eliminator, sure grip and 3:23's. His rear tire size is 255-60-15 on stock 15x7 rallye rims.

 

[Torkmnstr]

Hey vso, I have that same set up in my 69 rr. I have 295/50/15's on 15x10 rims in the back and she handles like a dream. In first it will snap your neck too! What are you wondering about the handling, are you gonna track it? And welcome to the site!

 

[vso737]

Hey vso, I have that same set up in my 69 rr. I have 295/50/15's on 15x10 rims in the back and she handles like a dream. In first it will snap your neck too! What are you wondering about the handling, are you gonna track it? And welcome to the site!

____________________________________

I should get my car Monday from the shop. I had the 4 speed manual replaced with a TCI 727 street fighter tranny and swapped out the 3.91 gears for 2.76. I will now have a nice freeway cruising machine.

Can't wait to get it on the road..............................

LG,
Mike

 

[mopar 3 B]

I hope your engine likes the combination. I once swaped the 4:10's with 3:23's the engine likes to run at 3400 rpm on the hwy that put it well over the speed limit.

 

[GetX'd]

I have a 68 GTX with that combo - engine is a 440 stroked to 494. She handles fine - except I put a 3500 stall this go around and it takes some getting used to.

 

[HT413]

I'm running a 727 and 4.10's, but am running a tall tire which effectively puts me right in the neighborhood of a 3.91, maybe a bit closer to the 3.80's. I'm at 3000 rpm cruising on the highway at about 65 mph, which is just find for me as I only cruise locally to being the kids for ice cream or to the park or to a local cruise night.

I had 3.23's before and boy did the 4.10's wake the car up.

 

[vso737]

I'm running a 727 and 4.10's, but am running a tall tire which effectively puts me right in the neighborhood of a 3.91, maybe a bit closer to the 3.80's. I'm at 3000 rpm cruising on the highway at about 65 mph, which is just find for me as I only cruise locally to being the kids for ice cream or to the park or to a local cruise night.

I had 3.23's before and boy did the 4.10's wake the car up.

_____________________________________________________________________________________

I also installed a 2400 stall converter. I was clocking 2600 RPM with the 4 speed at 60 MPH and with the 727 I calculated that I would be at 2800 RPM's with the 3.91 gears.
NOW, my calculations indicate I will be around 2000 RPM traveling at 60 MPH with the 2.76 gears. I think the 383 with the 750 carb will enjoy the freeway cruising much better..........I know I will.
I live in suburbia and do most of my driving in either back country roads or the freeway.

I love my 1930 Model A S.C. with the '68 327CI and 1993 4L60 trans. I have 3.73 gears and that overdrive allows me to cruise at 1900 RPM traveling 60 MPH on the freeway.

The way I look at it, the ONLY thing better for me is to have an OVERDRIVE transmission. But I will be able to live with the current setup just fine.
Can't wait to get it on the road.

 

[HT413]

Regarding the converter stall rpm - talking to Frank Lupo at dynamic, a quality converter might footbrake stall to 3000 but drive perfectly well at 2500 rpm, and in frank's words, slip even less than an OEM converter and certainly less than a budget 'loose' converter.

Now you didn't come out and say that converter stall was an issue with those 2.76's but it certainly was a major consideration for me and the sole reason I chose dynamic to make my converter for my 95% street and (hopefully one day) 5% strip car.