Putting POSI Gear

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salhi_aemr

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I have a 73 Mach 1 with 351 4V CC Heads, it has the FMX transmission. also it have 9 inch ford open differential 28 spline axle.

I would like to install 3.5 gear ratio on her,

would you guys recommend this 3.5, its going to be mainly for street driving no racing or much highway. Also could someone recommend a specific part?

Also how much cost I am looking at to install it.

Thanks

 
salhi_aemr,

The 3.50 would work with your with your stated driving scenario. Here are some websites that might be an option depending on your budget. I was lucky and found a traction lock third member local at a very reason price and had it rebuilt with a 3:55:1 for my AOD.

Here is a rear end third section from Quick Performance at a very reasonable price.

http://www.quickperformance.com/Ford-9-Complete-Center-Section-Third-Member_p_36.html

http://www.speedwaymotors.com/Ford-9-Inch-Posi-Traction-Third-Member-Assembly,6788.html

mustang7173

 
salhi_aemr,

The 3.50 would work with your with your stated driving scenario. Here are some websites that might be an option depending on your budget. I was lucky and found a traction lock third member local at a very reason price and had it rebuilt with a 3:55:1 for my AOD.

Here is a rear end third section from Quick Performance at a very reasonable price.

http://www.quickperformance.com/Ford-9-Complete-Center-Section-Third-Member_p_36.html

http://www.speedwaymotors.com/Ford-9-Inch-Posi-Traction-Third-Member-Assembly,6788.html

mustang7173
I am looking at this as well I have been searching locally for a complete 3.00 (I think 3.5 will be too many revs on the occasional highway) I would like a limited slip if I am doing the change. There seems to be a lot of options on the quick performance page and I am not sure what ones to pick. My other option it the local performance shop will rebuild mine with 3.00 and trac lock for a price. ($980!)

 
I am installing new motive 3.50 gears and a ford racing traction lok unit this weekend. I will let you all know how it turns out and driving impressions.

 
Mine is stock too and its 2.75 Conventional Rear Axle, Please let me know how it drives and if its a big difference. I have a mild cam on a 351C with 4V CC heads flatt tappet cam with FMX tanny.

ALso once its done let me know what part you bought the brand and how much it cost you?

 
Hello Amer, well I ran into a bit of a snag. When converting from a conventional rear (open diff) to a ford traction lok special stepped down bolts are required for the install. Yukon part# YSPBLT-014 is the part number you need, you will need 10 of these bolts. I just ordered a set and hopefully will have them by friday. The gear set I am going to use is motive F9-350 (3.50 ratio) and the trac lok is fms-m-4204-f28a, also you will need 4 ounces of friction modifier to add to the gear lube part# fms-m-19546-a1. The master install kit is part# R9RMKT, this has all of the bearing and races you will need for the installation of the gear set. The ring gear bolts that come with this kit WILL NOT work with the trac lok so you will need the bolts I mentioned earlier. We have set up several gear sets without to many problems so hopefully these wont be to bad.

Regards, Mike

 
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I just looked all the parts Mike and it doesnt look expensive, I want you to give me your opinion once you drive your car, is it going to be worth it? Also will it fit my axle shaft now 28 Spline?


How much is the shop charging you to do it or are you doing it yourself?

 
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The traction lok I ordered is for 28 spline axles. I will be installing them myself, shops around here charge $300.00 to install gears if you supply the parts.

 
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I would go with the link that Mustang7173 posted...... http://www.speedwaymotors.com/Ford-9-Inch-Posi-Traction-Third-Member-Assembly,6788.html

Hard to beat that price with posi already set up. All you have to do is pull your pumpkin and drop in the new one and done. You will absolutely love the 3.50 gears. It will wake up that motor ALOT. I have 373 gears in mine and love them. A little steep for a long road trip but around town they are a blast. A gear change is one of the most seat of the pants bang for your buck upgrades you can do.

 
I would go with the link that Mustang7173 posted...... http://www.speedwaymotors.com/Ford-9-Inch-Posi-Traction-Third-Member-Assembly,6788.html

Hard to beat that price with posi already set up. All you have to do is pull your pumpkin and drop in the new one and done. You will absolutely love the 3.50 gears. It will wake up that motor ALOT. I have 373 gears in mine and love them. A little steep for a long road trip but around town they are a blast. A gear change is one of the most seat of the pants bang for your buck upgrades you can do.

It probably wouldn't hurt to remove the back wheels and axles before pulling the pumpkin;)

 
That looks like its a great deal, will be on my bucket list

 
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