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Discussion Starter #1
Hey Guys- I have a 1967 fastback with 390/4 speed. Want to bring the car back to as close to original as possible as I have a lot of matching numbers for this car. Have 2 Toploaders I am going to build for the car, one wide ratio and one close ratio. I see the correct wide ratio transmission is RUG-M, but cannot find any information on what code Toploader was used for the 390 close ratio. 1968 was RUG-AD. Nobody shows anything for close ratio in a 67 with 390. RUG-N is for the 289, but says nothing about the BB. Anyone on here ever run into this? Thanks in advance....
 

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Don't recall ever seeing but 1 or 2 manual trans Mustangs in 67/68 models. They were always wide ratio as I recall.
And,RUG-M (or RUG-M1 or M2) is all the MPC lists...... doesn't look like there was a CR transmission used with the 390 in
the Mustang in '67.

In '68 they do list a close ratio in the 390 GT........ RUG-AD
 

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Discussion Starter #3
Yeah, that is what I found as well. Hope the wide ratio works out well with the gears I plan on running....Thanks for the response!
 

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Bucky, not sure why one would even consider the close ratio. The cars drive better with the wide. Are you doing the rebuild yourself ? There are even wider gearsets available. LSG
 

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Discussion Starter #5
Yes I am doing the rebuild myself. I was not planning on utilizing the original 3.00:1 rear axle ratio, that is why I considered the close ratio.
 

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Buck, what axle are you considering ? And why would you think a close ratio trans would help ? I would keep the 3.00, but consider the 2.98 1st gear with wide or the 3.01/2.08/1.47/1.00 gears with the 3.00 axle. The wider sets are MUCH more street friendly. Don't see a real use for the close ratio stuff. LSG
 

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The 390 has such a wide torque curve there isn't any need for a close ratio box if you're not racing the car.
 

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Discussion Starter #8
Was considering 3.50 or 3.70 rear axle ratio. I do not plan on any highway driving. Had 3.55 in my 69 FB and was very happy with it. This will be my first 390, that is why I was asking. I am very familiar with the Chevy Muncies from that era and found wide ratios worked best with 3.55 and lower. Close with 3.55 and higher(numerically). Thanks for the advice, I will build the RUG-M to start with in the car and keep the RUG-AD on the shelf.
 

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Interesting choice of rear end gears with the 390.

Come to Texas, where there are 80 MPH speed limits, and find out what a 3.70 sounds like at sustained speed.

Depending on your wheel tire set up, you are looking at 3800 +/- at speed.
 

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Discussion Starter #10
Nowhere here in NJ to do that type of sustained driving even if I wanted to. We are talking about something that I will probably not even drive monthly. Car will never see rain and probably only go to car shows or pick my kid up from school on a nice day. I have other “practical” cars, why not build a fun one?
 

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Discussion Starter #11
Another option is I have 2 center sections for the rear. Guess I will build a 3.00 and 3.50/3.70 and see which I prefer. Just wanted to confirm that a close ratio was never offered for the 1967 Mustang with 390 engine. Thanks to all....
 

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With a 3.50 and 235/60x15 tires the engine turned 3,000 rpm at 60 mph. That's fine for a SB, but it creates nothing but noise and a quickly drained gas tank with an FE. When I now shift into 5th it's as if the car undergoes a transformation. If you're keeping the engine stock a 3:00 will still allow you to break the rear end loose if you want to and will be just fine. Just one person's opinion.
 

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I have other “practical” cars, why not build a fun one?
Build away my friend!

I caught the fact that you said no highway use and only driving it occasionally. Just build it the way you want and come back and tell us about all the fun you're having with it!!

Allen
 

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im running a factory 3:20/3:25? gear from a 68 GT behind the 390 in my 70. It's not bad on the highway at 70, but it could use an overdrive. I don't have a tach in that car to know the RPM's.
 

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Where do you find those ratios? The MPC lists close as 2.32 low and wide as 2.78 low.
 

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^ You're talking about transmission internal ratios?
Those are in the Ford shop manual...... at least for '68 they are. (I didn't bother cracking the '66 book)
 
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