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Topic: would a 7.5 rear work in this case? (Read 3733 times) previous topic - next topic

would a 7.5 rear work in this case?

I have the stock 7.5" rear with 2.73 gears...I'd like to run anywhere from a 3.08 to a 3.55 gear. now my questions are this:
1. can I run a 8.8 posi unit?
2. if not where can I find a 7.5 posi unit?
3. would the 7.5 stand up to the occasional drag race, and street beatings? if not how'd you beef it up?

Now for another question...What does the 87-88 3.8 v6 powered Coug/T-bird use for rear gearing? I'm gonna try to pick up a '87 t-bird for parts
'83 Cougar *the never ending project* warmed over 306 v8,c4,8.8 posi with 5 lug conversion
'91 mustang strictly street-in progress
'00 f150 7700-Mean Green: jet stage 1 chip,ported upper intake with 1" spacer,'04 Super Duty intake with injectors,summit racing short tube headers with true 2.5" duals with smithy's glasspacks!

Re: would a 7.5 rear work in this case?

Reply #1
1. NO 8.8 traction lock (posi) is too big.
2. Ford Racing sells 7.5 Traction Lock (posi) units.
3. Mabey. If you don't use slicks (slicks=broken rear end). Also depends on how much hp ya got and what type of engine ya got.

I think 87-88 V6 Birds/Cougars had a 7.5" 3.27 gear.
88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, bunch of other stuff.

Re: would a 7.5 rear work in this case?

Reply #2
1. No. You need a 7.5" traction-lock unit (fords do not use "Posi").

2. You can find one in an 83-86 Turbo Coupe, 84-86 XR7 Turbo, 87-88 T-Bird Sport V8 and 87 Cougar XR-7 V8. Of course it was optional in all other trim levels, but the above ones had a 7.5" traction lock as standard equipment

3. Some people have had success using the 7.5", but not with a bunch of power. Anything better than a stock 5.0 HO and you'd probably be pushing it. Adding slicks would be like driving nails into the coffin. You can beef them up a bit (a girdle-style cover that supports the diff unit is available, and you might be able to get stronger diff units) but for serious duty an 8.8" is required

4. I believe most 87-88 V6 birds/cougs had either a 3.08 or 3.27. I installed the 3.27's from an 87 V6 'Bird into my old Sport
2015 Mustang GT Premium - 5.0, 6-speed, Guard Green - too much awesome for one car

1988 5.0 Thunderbird :birdsmily: SOLD SEPT 11 2010: TC front clip/hood ♣ Body & paint completed Oct 2007 ♣ 3.55 TC rear end and front brakes ♣ TC interior ♣ CHE rear control arms (adjustable lowers) ♣ 2001 Bullitt springs ♣ Energy suspension poly busings ♣ Kenne Brown subframe connectors ♣ CWE engine mounts ♣ Thundercat sequential turn signals ♣ Explorer overhead console (temp/compass display) ♣ 2.25" off-road dual exhaust ♣ T-5 transmission swap completed Jan 2009 ♣

Re: would a 7.5 rear work in this case?

Reply #3
You could always go with a full locker in your 7.5.....This particlar locker can be installed in an open carrier.....
http://www.powertrax.com/lockright.html

Here's the application chart:  The 7.5 is part #1830  The 8.8 is part # 1821.
http://www.powertrax.com/mercurylr.pdf

Both Jeg's and Summit carry them.  When I ordered mine Summit had the better price.
-- 05 Mustang GT-Whipplecharged !!
--87 5.0 Trick Flow Heads & Intake - Custom Cam - Many other goodies...3100Lbs...Low12's!

Re: would a 7.5 rear work in this case?

Reply #4
the 3.08 7 1/2 dominates most of your bone yard resources.  Look for the specific models thunderchicken points out to save time on your search. the whole 7.5 debate has gone around before and some say its better , some say its a lost cause and not worth keeping.  I personally dont know but there are topics and detailed research into the pro's and cons of each.  Just from what ive read on others digging into it, id think the trac loc 7.5 would suit me just fine for a rather agressive powerplant.

Re: would a 7.5 rear work in this case?

Reply #5
Quote from: 86Tbuzzard
I have the stock 7.5" rear with 2.73 gears...I'd like to run anywhere from a 3.08 to a 3.55 gear. now my questions are this:

2. if not where can I find a 7.5 posi unit?
3. would the 7.5 stand up to the occasional drag race, and street beatings? if not how'd you beef it up?

Now for another question...What does the 87-88 3.8 v6 powered Coug/T-bird use for rear gearing? I'm gonna try to pick up a '87 t-bird for parts


I have a 7.5 trac loc carrier that I would like to sell. This has good clutches in it, bearings and races, and ring gear bolts are included. I would sell it for $100, or make me an offer. I have a couple pictures because I was going to put this on ebay. If you would like to see the pictures please let me know. Contact me at dontnonottin@yahoo.com

My 7.5 did stand up to drag racing once a year until I had deflated my street tires to 15lbs. At that point I broke the drivers side bearing cap and the ring gear. I have upgraded to an 8.8 due to breaking the 7.5. Someone make a girdle for the 7.5 but you have to search to find it.
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Re: would a 7.5 rear work in this case?

Reply #7
ok here are my PLANNED mods...HO intake *upper (extrude honed), lower, injectors, sensors the whole 9 yards* B&M transpak for AOD. It should be able to handle that right?
'83 Cougar *the never ending project* warmed over 306 v8,c4,8.8 posi with 5 lug conversion
'91 mustang strictly street-in progress
'00 f150 7700-Mean Green: jet stage 1 chip,ported upper intake with 1" spacer,'04 Super Duty intake with injectors,summit racing short tube headers with true 2.5" duals with smithy's glasspacks!

Re: would a 7.5 rear work in this case?

Reply #8
Quote from: 86Tbuzzard
ok here are my PLANNED mods...HO intake *upper (extrude honed), lower, injectors, sensors the whole 9 yards* B&M transpak for AOD. It should be able to handle that right?



yes,it won"t impose a problem till you exceed 300 h/p or add slicks into the mix



i am running a 87 5.0 bird

long tubes, h pipe , mac lers, h.o intakes, throttle body, underdrives, electric fan ,14 degree initial timing, etc  with the 7.5 open rear diff  car pulls strong for what it is and the 7.5 showed almost no wear at the cars 130,00 miles


i swapped in 3.73's lastnight from a late 80's aerostar van also look for limeted slip units there as most have them
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Re: would a 7.5 rear work in this case?

Reply #9
Quote
would the 7.5 stand up to the occasional drag race, and street beatings? if not how'd you beef it up?


Quote
Mabey. If you don't use slicks (slicks=broken rear end)

(7.5" rearend+ drag racing= broken 7.5"rearend)

7.5" rear for drag racing:laughing: :laughing: :laughing: :laughing:  :rollin:  :rollin:  :rollin:  :rollin:  :rollin:  :rollin:

man after i saw what happend to my stock 8.8 rear  i could only imagine what would of happend if it was an 7.5

if you really want to use your 7.5 for drag racing i could only suggest a few things you should bring with you when you go drag racing..

1 a large bucket
2 a band aid
3 some oil dry
4 about $200.00
5 another $400.00 or so.. ;)

the large bucket is for all the broken parts...

the band aid will be for your broken ego for busting a rear on the track..

the oil dry is for the mess you make with that 7.5 rearend when it blows apart..

the $200.00 is for the tow truck ride home..

and the $400.00+ is for the 8.8 rearend you will need to buy


now what i typed was just my wacky sence of humor

and is not intened to piss anyone off ;)

but i do strongly do not suggest you drag race with a 7.5 rearend..


Nick
Quote
there's only about a half a dozen man made objects that are herd by the human ear below 40Hz,a pipe organ,thunder,the space shuttle lifting off,a jet airplane taking off or landing,a large canon,an atomic bomb ignited in your back yard and the heat wave afterward oh wait you would be dead so you would'nt hear it scratch that!,and maybe beating your hear against a wall less then 40 times a second..rap music is'nt one of them!thats 40-60Hz@100+db the moving air is under 40Hz

Re: would a 7.5 rear work in this case?

Reply #10
...yeah...because we all run H/C/I V8 cars, all with blowers, and all with 5-speeds

we ALL need to get rid of the 7.5, even the 3.8 guys, we're gonna break em
It's Gumby's fault.

Re: would a 7.5 rear work in this case?

Reply #11
I agree with Nick (Blown306Cougar). I'm speaking from experience. I had broke mine at the line while drag racing with a stock 5.0, stock clutch, t5 5speed, and 3.73 tracloc. I was aired down street tires (Goodyear Aqua treads).
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Re: would a 7.5 rear work in this case?

Reply #12
Quote from: Tbird232ci
...yeah...because we all run H/C/I V8 cars, all with blowers, and all with 5-speeds

we ALL need to get rid of the 7.5, even the 3.8 guys, we're gonna break em


:flip: :raspberry

ok if you have a slow ass V6 or a turbo 4CYL that is as slow as Shawn's T/Birds ok then you could get by with a 7.5 but if you ever plan to have a little fun with your fox body Cougar or T/Bird and your going to keep the 7.5 rearend then plan it blowing up on you one day..

all it's going to take is 155HP and 3300 to 3400pounds of car and one good beating.. and BOOM!

Nick

by the way shawn lol  :rollin: what does H/C/I V8 cars mean anyway?:rollin:

EDIT oh and are you going to Ohio this week Shawn? if yes your going for a ride and maybe if your a good boy i'll let you drive it  :evilgrin:
Quote
there's only about a half a dozen man made objects that are herd by the human ear below 40Hz,a pipe organ,thunder,the space shuttle lifting off,a jet airplane taking off or landing,a large canon,an atomic bomb ignited in your back yard and the heat wave afterward oh wait you would be dead so you would'nt hear it scratch that!,and maybe beating your hear against a wall less then 40 times a second..rap music is'nt one of them!thats 40-60Hz@100+db the moving air is under 40Hz

Re: would a 7.5 rear work in this case?

Reply #13
H/C/I=heads cam intake

turbo 4's being slow huh? someone sure has a big dick and no hand to stroke it...
It's Gumby's fault.

 

Re: would a 7.5 rear work in this case?

Reply #14
Oh look, someone's attitude has returned since being humbled by the dyno run that ruined all their stupid shiznit-talking.

That's the problem with you people that whip it out and try to wave it in everyone's faces.. when it gets caught in the zipper you look even dumber than you did with your dick in your hand. Why not just skip the adolescent bullshiznit to begin with? It doesn't make you a better person because you think your car can pass anything on the road except a gas station, and you can't resist talking.. nay, bragging about it every chance you get. Hell, I'm probably the most immature person I know and your shiznit embarrasses me. That should tell you something.. but I doubt it will.

"Huge member!!!" indeed.. you're acting like a total dick to Shawn. He may be a prick at times, but so are we all.. (some of us more than others) and I do tend to consider him in a friend-like manner. How about you knock off the bullshiznit now before this thread gets ugly?

The world does not revolve around the small-block V8, no matter how much you wish it did.. and it's people like you that turn people like me off to them with your constant bitching about anything that isn't one. I happen to own four of them now, including two 5.0 HOs and one pickled 351 HO, and I still wouldn't make as much of an ass of myself over them as you have. ****ing get over it already. If Shawn likes his TC, what does it matter to you? If someone likes 6-cylinder engines, 4-cylinder engines, even 5- or 3-bangers, what does it matter to you? Be happy with your own shiznit and get on with your life. Chances are, someday you'll run into someone who loves their non-V8 more than you love your V8, and they just MIGHT embarrass you. Then what will you do? Won't be able to bitch about a bad dyno run that time around.