T5 Gearing w/ 292 ina Ranch wagon

[DanTudor57]

This is s topic we may have discussed in passing a long time ago, but would like to revisit... I am now shopping around for a few more parts and need some help.

Based on my following setup/requirements how do I figure out the correct/ best rear end gear I need - Can you make some recommendations?

Vehicle:        '57 Ranch Wagon
Engine:         mild 292, blue thunder intake, very tame 4-brl Holey (may move back to 2brl intake/carb)
Exhaust:       3 inch pipe with huge mufflers for loow noise.
Transmission: '93 Cobra spec WC t-5, with stock gearing of 3.35:1.
Wheels:        17 inch, almost regular profile tires
Driving style:

• Commute, 55-75 MPH highway speeds 80% of the time.
• No racing..but I need to be able to quickly merge into fast moving highway traffic.
• Minimal loading of vehicle.
• Absolutely no towing
• MPG are of top priority

I am currently using an 8.8 IRS  from a TBird but might go with an 8.8 straight axle out of a '97 explorer (my stock rear end was trash).  Stock gear available on these axles are 4.10, 3.73, 3.55, 3.27, 3.08

[Frankenstein57]

I'm planning to use the t-5 behind a mild 351, in a ranchero. Yesterday I picked up a 3.70 carrier which we believe will be a good street gear, should have good get up and go, and good mileage with the od. The 3.55 also might be a good choice. happy motoring,  Mark

[bagboy]

I have 57 RW w/ 351w 4v.Had 3:50 gears with AOD [.067 od]. Changed to 4:11,pulls hills much better also comes off the line good.Mpg was 22 before change will update soon.Did you see my post on R/sway bar?

[57AGIN]

Dan:

If it is mileage you are looking for, your existing 3:35's may be a pretty good choice.  Depending on what tire size (not rim size, but overall diameter), you could probably even go to a 3:10 or 3:00 gear.  As I recall, the 292 has pretty good torque so it should be a pretty good all around package.  I don't think you will have any problems with acceleration, either from a standing start or merging lanes (merging lanes, you could always grab a lower gear to get into the lane you want). 

Looking forward to seeing the finished package at some of the shows out here.

Bob
57AGIN

[DanTudor57]

Bob, the 3:35 was T5's first gear ratio.

I found the complete gearing for the Cobra T5 Transmission..

Torque Max (lb/ft)   ----> 310

Gear Ratios:

1st   2nd   3rd   4th   5th   R
                  
3.35   1.99   1.33   1.00   0.68   3.15

[57AGIN]

Dan:

Thanks for clearing that up.  Given the fact that I don't have a long history of playing with lots of different cars with a variety of transmission and rear end gearing, Here is my take on the matter. 

In 1964 I traded my original 57 in on a Mustang.  It had a 289, Borg-Warner T-10 4-speed and a set of 3.80 rear gears.  My T-10 was the wide ratio one, with a 2.78 1st gear.  That coupled with my 3.80 rear end gears figures out to a ratio of 10.56:1 for taking off from a standing start.  Naturally, without an overdrive and a set of 3.80 gears in the back, the engine RPM was a bit high on the freeway.  But, it did jump off the starting line at Lions pretty good.

Now to your set-up.  The T-5, having a 3.35 1st gear, could be teamed up with a 3.10 rear end and your take off ratio would be 10.38:1.  This is still a pretty good low (1st) gear set-up.  Back in 1965 the stock gearing for the Mustang with the 4-speed was 3.0, giving a take off ratio of 8.34:1.  Which was just ok.  Your T-5, having a 5th gear with a .68 ratio would give your wagon a top end freeway driving ration of 2.10:1, which would have you practically ideling at freeway speeds.  You could probably go to a 3.5 rear end gear and have great torque and acceleration at start and still have a very good top end driving ratio of 2.38, which is still a good mileage gear for freeway driving.

I'll bet James or Hurricane Hoosier could give you some pointers, too.

Just for fun, I've attached a photo of the original Mustang with me at a tender age of 21 inside and a photo of my new daily driver.

Bob
57AGIN

[DanTudor57]

Nice 'stangs...Old habits are hard to break... not that we should..

I've been hearing mixed reviews on the 8.8 I'm planning to use.

If I decide to stick with the IRS, then I'll have to do quite a bit more work to get it functional. If I go with the '97 Explorer 8.8, it'll be much easier to adapt. Decisions...

Now that I'm going down the road of restarting work on my Ranch Wagon, I'll have to start raising money! Time to really sell the country sedan.

So does anyone have any input on the 8.8 Tbird IRS, or the 97 Explorer 8.8 straight axle?