any of the ones you selected will do just fine. and they are all about the same price, so that is not a factor. in the end i would probably go with the eaton trutrac diff, but that is a personal preference more than anything else.

 

Cool. Only difference appears to be spider vs. worm gears. Care to school me as to what that means?

 

I like the Eaton TrueTrac. I like the pinion gears as opposed to the spiders that most have. It's a durability improvement IMO.

 

I was down the same path as you. Did the true-trac with 3:40 gears! Planning a 331 in front of it. If you plan to hit the strip with slicks/super sticky radials you might want to go 9" with that 331.

 

The additional weight and parasitic loss of a 9" seems like total overkill for what I intend (~300hp motor on 225 street tires). 95% sure my car will be relegated to street use only.

I am curious re. the usual pain points for the 8" though...anything I can do in order to ensure a long trouble free lifespan, I am willing to do.

 

The TrueTrac is way different than any clutch-type or locker. It's a superior design that solves the old "differential problem" that open/clutch/ratchet/lockers suffer from. It's not a matter of worm gear vs. spider gear. Spider gears just transfer power. The gear mechanism in the TrueTrac is what actually operates the torque splitting abilities of the differential.

 

Thanks! That's exactly the info I was looking for. I was kind of split between the Currie and the Eaton but it seems the TrueTrac is a better design.

 

I would check out TJ 8 inch Ford Rear End Maverick Street Rod Mustang Posi 550HP 9 | eBay

 

That seems like a pretty solid deal...~$1200 with TrueTrack installed, looks like.

I've seen other users here report positive experiences. Definitely will keep them in mind.

 

I just put a TruTrack with 3.55 gears in a 8" behind my 347 and I love it. HUGE difference putting the power down, especially around corners. With the open diff any throttle mid corner would spin up the inside tire and just make noise. Now it bites, rotates, and accelerates. You can very accurately steer with the throttle. It feels great.

 

I have the Yukon unit in my car, no complaints at all.

 

Whatever you'd like for a differential, but put it in a '67 and up carrier.

 

If I didn't already have a 9" Traction-Lok™ I would convert mine to the TruTrack™. The TL works by using a friction clutch pack to limit the slippage of the wheel with the least traction, hence the generic name "limited slip". It even has a cup on one side that uses differential (spider) gear pressure to increase the pressure on the clutch pack under torque. This is identical in every way to GM's Positraction™.

The TrueTrack™ alternatively uses gearing to transfer engine power to the wheel that has the most traction. I saw something recently that seemed familiar, so I went back and took a look. Sure enough, although the differential gears are straight cut (and more of them), this differential works on the same principle, and was in widespread use more than 20 years before the first Mustang rolled off the assembly line.

 

I was going to ask if that was a Sherman tank and when I clicked on the "Quote" box the url for the photo popped up answering my question!

 

Google torsen differential for a bunch of info about how they work. I bought an Eaton from Randy's ring and Pinion with 3,80s. about $800 IIRC, but that was 8 years ago. I've been as happy as a lark with the way it sits in the garage after tearing the rest of the car up during my first track day after putting it in.

 

I am currently doing the same mod as mentioned. Going to change to locker unit to my 8 inch rearend. Has anyone ever used national drivetrain posi unit? It comes with ring and pinion. Just wondering if this would be worth buying or if it's a cheap made budget locker.


Ring and Pinion Bearing Install Kit New Posi Ford 8" 3 40 Ratio | eBay