Best Gear with Procharger

[80FoxCoupe]

315 has its own differential, 355/373 share the same differential. The housing itself is the same.

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[LSchicago]

I am running 285x19 Michelin pilot sports in the back. No tracking, this is just a fun street car. How do you like the 3.55 gears? Going from 3.15 I have to do the whole pumpkin I believe.

I love the 3.55's, but I needed Drag radials with just an E85 tune on my car (no boost) to eliminate the wheel spin. You may need to up your tire game. 10PSI of boost on E85 brought wheelspin through first, second and screeching on the 3-4 & 4-5 shifts. I went to the tall street R's, then bumped up boost to about 15#. Traction is back. going up to 16# in spring.

 

[Stangmang]

You make more power than the OP, and also have a 10r80.

The OP's setup is the mildest boosted combo possible. Traction from a dead stop on anything short of a drag radial should be a problem now. It doesn't sound like he is trying to make hits from a dig on a regular tire. Slow roll im sure its fine. Ive ran 315, 355 and 373 with a procharger, with a 6r80 from 600whp all the way to 1300whp. Based on the OP's original post, 373 would be my recommendation.

Definitely not trying to make hits from a dig as you say. My end set up by spring will be adding headers, the ported 18 mani, bap and a 3.5 pulley to hopefully hit near 10 psi on pump. Hoping to be around 650ish wheel at that point and I don't have any intentions on going any crazier...of course that's what I said after the basic first tune.

The interest in smaller gears are really just to "feel" a bit more pep around town and also get the blower to spin up quicker along with the other mods to work with the direction on how the motor is built to work. I'm thinking to go with the 3.55 pumpkin, see how it shines and then try the 3.73s if I still think it needs it.

 

[80FoxCoupe]

Definitely not trying to make hits from a dig as you say. My end set up by spring will be adding headers, the ported 18 mani, bap and a 3.5 pulley to hopefully hit near 10 psi on pump. Hoping to be around 650ish wheel at that point and I don't have any intentions on going any crazier...of course that's what I said after the basic first tune.

The interest in smaller gears are really just to "feel" a bit more pep around town and also get the blower to spin up quicker along with the other mods to work with the direction on how the motor is built to work. I'm thinking to go with the 3.55 pumpkin, see how it shines and then try the 3.73s if I still think it needs it.

I tried.

 

[Stangmang]

I tried.

You did, and thank you sir for all your information! I was just trying to say that I'd have to get the 3.55 pumpkin first anyways, so I might as well see how I like it before ripping it apart to add more gear.

Thanks again

 

[80FoxCoupe]

You did, and thank you sir for all your information! I was just trying to say that I'd have to get the 3.55 pumpkin first anyways, so I might as well see how I like it before ripping it apart to add more gear.

Thanks again

You do not need to buy another housing. Just get the gear you want and corresponding differential, install that in your housing.

 

[Stangmang]

You do not need to buy another housing. Just get the gear you want and corresponding differential, install that in your housing.

Really, I didn't know that you could. Thanks!

 

[schmeky]

Very happy with my Torsen equipped 3.55, A10, Procharger Stage 2 HO, with an estimated 640-650 whp.

With any set up similar to this, proper rubber is critical. I am running the Nitto 555R2's in 305, it's still spin city below 45 mph with full throttle.

 

[80FoxCoupe]

Traditionally, people fear the gear. LOL

 

[LSchicago]

Traditionally, people fear the gear. LOL

I am not one of those. I put a 4.10 in my 73 Cutlass 455 4 speed, And told my dealer the GT he got for me must have 3.55's, because that was the highest numerically offered. Add traction, and let it rip!

 

[Angrey]

I'm pretty sure the 3.15 only comes compatible in the Aluminum housing. The ring and pinion sets for 331, 373, 355, 409, etc will work in the iron housing. As far as I know they're not interchangeable between the aluminum (3.15) and the iron housing (331 and up).

 

[andrewtac]

I'm pretty sure the 3.15 only comes compatible in the Aluminum housing. The ring and pinion sets for 331, 373, 355, 409, etc will work in the iron housing. As far as I know they're not interchangeable between the aluminum (3.15) and the iron housing (331 and up).

It is the differential that is different, the housings are the same.

 

[80FoxCoupe]

I'm pretty sure the 3.15 only comes compatible in the Aluminum housing. The ring and pinion sets for 331, 373, 355, 409, etc will work in the iron housing. As far as I know they're not interchangeable between the aluminum (3.15) and the iron housing (331 and up).

Nope, ive had a 373 in my originally equipped 315 aluminum housing.

 

[Angrey]

Interesting, US Gear's catalog has an asterisk under their Super 8.8 Ring/Pinion sets that disclaims " *Will NOT fit earlier 8.8-inch straight axles found in previous generations. **Will NOT fit 2015-2017 Mustangs originally equipped with a rear-end housing with factory installed 3.15 gears. "

US Gear makes the FRPP gears, and I'm not so sure they don't supply Ford with the Ring/Pinions for the factory installed units.

 

[80FoxCoupe]

Interesting, US Gear's catalog has an asterisk under their Super 8.8 Ring/Pinion sets that disclaims " *Will NOT fit earlier 8.8-inch straight axles found in previous generations. **Will NOT fit 2015-2017 Mustangs originally equipped with a rear-end housing with factory installed 3.15 gears. "

US Gear makes the FRPP gears, and I'm not so sure they don't supply Ford with the Ring/Pinions for the factory installed units.

We did it with no issues. They may be insinuating that it is not work with the 315 diff, not necessarily the housing.

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