[t.mcginley.jr]

Hi guys,

I have a 1966 coupe with a stock 289 v8 and c4 transmission. I wanted to swap out the stock gears in the rear end (I believe they're 3.00:1) so that I have a faster acceleration. I was looking at some sets and saw a 3.25:1 and a 3.55:1 ratio set. Any thoughts???

 

[Sick467]

Here's some thoughts - recently discussed in a different thread...

http://www.allfordmustangs.com/forums/classic-talk/264187-3-55-gears-sound-good-but-they-me.html

And so much depends on how, how often, and where you drive and if mpg's are important to you.

 

[Musclecarguy]

well how much acceleration do you want? is gas mileage a problem? it all depends on what your gonna do with the car. city, highway, track.

 

[blackstangcoupe]

i would do 3.55 or 3.73 both a good choice without hurting mileage too much

 

[t.mcginley.jr]

Thanks for the quick replies! I deffinitely don't plan on racing the car in any way, so high performance isn't my goal. I just drive it around on weekends. I live in South Jersey so its pretty suburban. I'm not too worrried about mpgs because I'm gonna be putting in a 4 bbl, manifold, cam and possibly new heads.

 

[Musclecarguy]

3.73s would be the bests of both worlds for what your looking to do. so my suggestion would be them just because you have some good off the line torque but the mileage isnt through the roof. i cant wait to get my stang outta storage and get my mods done and see how she rides with the 4.10s. hope you have fun playing with your car and smoking some little "honda" soup cans for fun.

 

[sweethotrods]

I'm running 289 C4 and changing up from 280s to 355s no more. Perfect for cruising and get up and go.

 

[Musclecarguy]

how does your car run and what kinda power? gotta let me know at some time what your 1/4 mile is.

 

[mic53mlb]

3.55s your best bet with your C-4. It'll rev high with anything steeper than 3.55 without overdrive.

 

[SDMustangRider]

^^^ So you think with 3.55 on the freeway using a C4, RPMs shouldn't run THAT high? Or at least high enough to where it won't be so anoying loud other than my exhaust?

 

[sweethotrods]

It all depends on how fast you want to go with the 355s its just fine 100mph or less and how often are you on the highway I myself like quiet and I always stick sound deadenr in my cars and I do not like to interrupt the police while eating there donuts roadside. If you are intending to drive faster and dont need great but good acceleration from the lights then the 325s will be just fine and quiet. Myself I will be going 355s but I think the 325s would be good for you. :hihi: Well guess what the wife just told me the 325s are going in her car so there ya go.

 

[SDMustangRider]

I'd love to have good/great acceleration on the road and to back my power up that's been built, but on the freeway, I'm mostly going to be at 70 mph. I guess if I'm lucky to find some 3.40's that might work just as well.

 

[sweethotrods]

If that's it 70mph definitely 355s no more no less if you like torque you will be happy with this. Giddy up :spoton:

 

[SDMustangRider]

Right on. Basically the only time I use my car on the freeway is going to work but I switch with my truck from time to time. Especially when it rains, I use my truck more just because it's bigger and more safer. I'm gonna try to find 340's first. Thanks. Sry fir thread jacking. Trying to keep it on the same subject.

 

[66 restomod]

I have a T5 and decided to go with 3.55 and Trac Loc.
Just got it and can not wait to put it in!

 

[Boat735]

Mine is on the way. I got the 3.55 ratio with Trac Loc as well. Did you get yours from that guy T.J. on Ebay?

When will you be installing them? I was wondering if I need to install new axle shaft seals. Maybe start a thread when you're done documenting the process and a before and after review. You're good at that kind of stuff...:bigthumbsup

 

[PaulS]

Driving with Trak-loc on the street is like driving in snow with four wheel drive. Everything is fine until you lose traction and then it is nearly impossible to regain control!
I will never drive a street car with track-loc again. I am unsafe enough with one wheel spinning!:yelwacko:

 

[SDMustangRider]

Would you recommend just a gear swap instead Paul?

 

[66 restomod]

Mine is on the way. I got the 3.55 ratio with Trac Loc as well. Did you get yours from that guy T.J. on Ebay?

When will you be installing them? I was wondering if I need to install new axle shaft seals. Maybe start a thread when you're done documenting the process and a before and after review. You're good at that kind of stuff...:bigthumbsup

I am going to have new bearings and seals put on the axles. I found a local shop who will press the bearings off and install the new ones for 25 bucks ( I supply parts).

I will probably do it around mid December when Chris comes home form college so he can help. I will make a new web page on my site to document everything.

I was surprised that you have to break in a new rear end pumpkin. Drive it around town for 10 minutes and then let it cool for 30 minutes. Repeat 3 times. It also need special additive for the limited slip clutch disks. Also need new copper washers so it does not leak fluid out of the bolts.

I can not wait to drive it. A friend told me the acceleration improvement will be like adding 75 HP to the motor. I hope so!

Good Luck and Be Safe
Ron

 

[t.mcginley.jr]

Yeah I rarely drive mine on the highway and when I do its never above 70 so I'm probably gonna go with the 355s also. If I cared about mpg's I would get the 325s but like someone else said.. if I cared about mpg's I would've bought a Civic.:rollgrin: