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Discussion Starter #1
I've been reading a lot of posts about what differential to stick in my 8" rear and can't decide. First a little back round car is a 70 coupe 302, 40 over roller motor with a 550 lift cam, Rpm intake , 670 carb, afr heads 1650 I think they are, and bottom end fully built.
About 5 years ago I changed the ring and pinion from stock to 3.25, which felt better but honestly just doesn't feel like it gets up and goes. I have a c4 with a bm shift kit and a 2200-2600 stall. My plan is to put a true trac in my 8" but I'm undecided on gears, do I go for the 3.80s or do I just go to 3.55, I'm not a track guy, rarely go but want to once in a while just when I get the itch, do some highway driving , and some city. Do I go 3.80 and upgrade the trans to an overdrive trans? Or just stick with 3.55?
 

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I've got a 8" third member with 3.80's and a powertrax locker. I've been thinking about swapping to 3.25's or 3.40's, but didn't want to spend the money. Maybe we could work up a trade... PM me if interested.

The 3.80's are just a little lower gear than I want. The gears are quiet...no whine or howl. The powertrax locker is a "lunchbox locker" that replaces the spider gears in an open carrier. It works well and is quiet except you can hear it "clunk" when it unlocks going into a turn and then "clunk" again when it locks back after straightening back out.
 

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Discussion Starter #3
Is it too high of a gear? Just trying to get a feeler for highway / around town driving. I would trade with you but I'm sure it would take forever for me to get my end back to you.
 

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It's really not bad. The only thing I don't like about it is, because I have a T5 with the 3.35 1st gear, I have to shift out of 1st before I make it through the intersection. With a taller 1st gear it wouldn't be bad at all.
 

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I think that's a good choice. The only negative I've heard about the true trac is the price.
The powertrax locker works well, but to me it's kinda embarrassing to turn sharp in a parking lot and hear the locker "clunk" while you turn and then "clunk" again when you straighten out because if people don't know what a locker sounds like they just assume something is broken on your car.... but some guys remember what a locker sounds like and hear the "clunk" and think it's cool.

As far as your gear choice, I love the 3.80's in every gear except 1st because my 1st gear is 3.35... but then again, I have overdrive.
 

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Discussion Starter #7
Yeah that's what I'm afraid of, 3.80 will be awesome up til 50mph and after that i think it's gonna be a killer
 

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Since you are planning on swapping the carrier and the gears the only thing you'll be re-using will be the case/housing and replacing everything else. Do you have any interest in just selling the 3.25 complete chunk?
 
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