[nolo941]

I am looking to swap out my top loader 4 speed for a wc t5 on my 66 mustang. The question is what is better for my vehicle The vehicle had a 3.00:1 conventional axle. The two choices I have is a .68 or .72 5th gear. Which is better?

 

[HoosierBuddy]

It's just not that big of a difference. With the .72 you would be running about 6% higher RPM in top gear...so maybe go for the .68?

Phil

 

[LeeFred]

Which is better?

The Toploader

 

[2nd 66]

FWIW I have a mild 289, 93 Cobra spec T-5 3.35/.68, 8" 3.40TL I did use the T-5 for a while with an open 3.00

 

[bdub4u]

while not an automatic, my AODE has a .64 rear ratio. the 3.80 rear i have works pretty good with the combo. good take off and rpms are pretty good on highway. i was actually just looking into a 5 speed swap but going wide ratio. id like to have the final in the .5's area and the other 4 normal gearing for when im not on the open highways.

 

[gjz30075]

With a 3:00 rear gear, I don't think you'll get into 5th with either of those ratios. They're
way too high. The engine will be lugging, trying to keep the car moving at the
low rpms it'll be at.

Just to put things in perspective, I had a 3:55 rear gear with a .68 fifth with 26.5" tire diameter and the engine was turning 2100 rpm at 70 mph. And this is with a
400 hp 331. I was able to run at 50mph or so in fifth. Anything less required a
downshift.

 

[LastDeadLast]

Just as a comparison.. I'm running 3.89 gears with a T5-z. It has a .63 ratio for 5th gear and that puts me right at 2000rpm at 60mph, at 70 right about 2500ish.

With your 3.00:1 ratio, I would go for at least the .72 ratio, but IMO, that might be too low (errr, high) unless you're hitting 70mph. A 3.55:1 gear set would serve you well.

-Shannon

 

[j persons]

I had a .80 OD in my FF Cobra with a 3.55 rear, 5th was great, I could even pull out to pass some one and didn't have to down shift, as long as I was going over 50MPH. 70MPH was a little less than 2500 RPM.

 

[ModStang]

.68 WC and 3.73s in my car and fifth gear does just fine on the highway. Plenty of pull once you get over 55 or 60. I can cruise in fifth under 55 but there isn't much for passing power.

 

[67Modcoupe]

The Fox body mustangs had a 2.73 or 3.08 gear with the WC T5, so a 3.00 is right in the middle of what the later model cars ran...which is why my old fox would get like 28 MPG on the freeway.

 

[Rorin67]

The Fox body mustangs had a 2.73 or 3.08 gear with the WC T5, so a 3.00 is right in the middle of what the later model cars ran...which is why my old fox would get like 28 MPG on the freeway.

This, exactly. With either of the ratios, you'll be close to a stock Foxbody. In my old Fox, 5th was great for freeway "economy" driving, not "spirited" driving (that required a downshift).