[69Goat1]

Originally Posted by PAUL K

I've had 3:90's with a spool in my car for the last 5 years. I can tell you spools suck for everything but going down the track. I just put 4:30's in with a locker and that is what made me realize how bad the spool was.
But another thing to think about, if you have a posi type differential and break an axle, won't the car be easier to control than with a spool?

Interesting you should mention that... I broke an axle about 3 weeks ago on the starting line with my stock clutch type posi from a 12 bolt from an 66 SS396 and the car just sat there - didn't move at all. Replaced the axle and all is good again. I do have C-clip eliminators.

I have this posi in one of my 69 GTO's and LOVE it on the street. The other 69 GTO is a full spool and even though I have and do drive it on the street you definitely make wider turns and do lots of backing up and trying it again...

[One bad 71]

Andrew, As everyone has said a spool is not very street friendly. Tears up tires hard to make tight turns in parking lots and it is not funn in the rain. I have a Detroit Tru trac I took out of my car for sale. It is a 3 series but I believe you can buy spacer rings that would probably be ok for a mild race mainly street car. I will cut you a screaming deal if you are interested and I could probab ly get a good shipping rate thru work. Email me if you are.

[92GA]

I'd stay away from the spacer too, if you're running slicks. Seen lots of ring gear bolts broken with those things. 40 years ago I was running a 69 Camaro with a 4 speed and used ring gear spacers in my 12 bolt. I broke at least 3 sets of ring gear bolts, from 3 differant manufactures. Switched to a 4 series carrier, problem solved.

[67drake]

They do sell thicker ring gears for 12 bolts so that you don't need a spacer behind it. Don't know if every ratio is available,but worth looking into.
I just looked for a thick ring gear for my 8.5 (Which they DON'T make!), but saw plenty on the market for 12 bolts.

[Old Man Taylor]

Originally Posted by andrewT

Thank you for all the help guys!! I guess I will stick with the posi idea regardless of price.



I need a 4 series one because I have 4.11 4 series gears. I wonder if I can get the 3 series posi and shim it to fit 4 series gears?

(I think you can only do that in the other order, am I right)

You can run a spacer, but the last time I checked the Eaton Brute Strength posi was only made in a 4 series. If you run a spacer it needs to be set up by a very competent specialist. A long time ago I ran a 10 bolt successully with a spacer (even racing it) until I sold it and updated to a 12 bolt..

[andrewT]

Originally Posted by One bad 71

Andrew, As everyone has said a spool is not very street friendly. Tears up tires hard to make tight turns in parking lots and it is not funn in the rain. I have a Detroit Tru trac I took out of my car for sale. It is a 3 series but I believe you can buy spacer rings that would probably be ok for a mild race mainly street car. I will cut you a screaming deal if you are interested and I could probab ly get a good shipping rate thru work. Email me if you are.

Jim

Is it for 33 spline? if so let me know, I will call Detroit tommorow and ask about the spacers.

My car is stick right now. The Truetrac is different from a locker, so it won't be a problem in a stick car on turns? (I have read that lockers and stick cars do not go well together from my brother who is a UMTR guy.

[71 Ventura II]

Another issue when running a spool on the street: If you do any highway driving where there are grooves/ruts in the asphault from big trucks be CAREFULL because the spool will cause unexpected lane changes! You will feel it pushing you.

Parking is always a concern because you are binding the axles. JD

[Region Warrior]

Dont cheap out, get the Eaton.
If you break that, need a stronger rear end to begin with.

Know 2 guys with Brute Strengh's that run mid 9's for yrs.

I have one with 4.11.s
Really want 3.55's in my current 70% street/25 strip car.
My racing buddy since the 70's(also runs 9's), and builds BIG power stuff for $ guys says DONT spacer it if your gon'a hook.
Make room for taller tires.

[thirdgen455]

Car still have sway bars? You could set it up like mine and not need a posi at all.

[andrewT]

Originally Posted by Region Warrior

Dont cheap out, get the Eaton.
If you break that, need a stronger rear end to begin with.

Know 2 guys with Brute Strengh's that run mid 9's for yrs.

I have one with 4.11.s
Really want 3.55's in my current 70% street/25 strip car.
My racing buddy since the 70's(also runs 9's), and builds BIG power stuff for $ guys says DONT spacer it if your gon'a hook.
Make room for taller tires.

Are the Brute Strengths a Posi or locker, or something like the true-trac?
Now that I have done more reading everything I see about the true trac in a street/strip environment is negative!

Originally Posted by thirdgen455

Car still have sway bars? You could set it up like mine and not need a posi at all.

it has both front and rear but they will be coming off and I will be putting in anti roll when the rear one comes off. Please explain though; you have piqued my interest.

[Region Warrior]

Andrew, its an Eaton type posi.
Supposed to have stronger case and guts.
Made by Moroso. How knows, maybe just a reboxed Eaton???
Never seen one apart.

[andrewT]

Originally Posted by Region Warrior

Andrew, its an Eaton type posi.
Supposed to have stronger case and guts.
Made by Moroso. How knows, maybe just a reboxed Eaton???

Thanks Mike

I have read guys saying that the clutch packs on the brute strength are so tight they chatter going around turns like a locker.

[Skip Fix]

They also make a thin gear 12 bolt 3 series to use on a 4 series posi/spool. Had to get one for the 3.73 and the spool in the Camaro/IA project 12 bolt.

[Old Man Taylor]

Originally Posted by andrewT

Thanks Mike

I have read guys saying that the clutch packs on the brute strength are so tight they chatter going around turns like a locker.

Mine does not chatter going around corners. The only way I'm aware of that will cause that is not using the correct oil in the differential.

[Gas455]

Is there much difference in driving with a detroit locker on the street and a spool??

My '60 has a 9" with a locker...and the '57 I'm building will be using the original 57-64 diff with 35 spline and a spool.

The '60 has been street driven for over 10 years...just fitted power steer this year.

Have never driven with a spool.

[Tom Vaught]

We ran Brute Strength stuff in a 64 GTO in 1971 in the low 11s. Never had an issue
once we installed the GM "service pack" axles to go with the rear.

Always liked that rear when it was set up properly.

Had a few friends wreck their late 60s Mustangs when they tried to run spools and slicks on the street.

A Ford 9" allows you to have a pig set up for a STREET gear/ Posi and a RACE pig set up with a spool and the right Drag Gears for your track (say an 1/8th mile deal).

Tom Vaught

ps Spending money several times to "save" money the first time is primarily due to inexperience. Some times you just have to bite the bullet and buy the good stuff initially.

[andrewT]

Originally Posted by Tom Vaught

ps Spending money several times to "save" money the first time is primarily due to inexperience. Some times you just have to bite the bullet and buy the good stuff initially.

I hope thats not directed at me. My buddy with a fox body has been doing everything twice because a) he is in a rush and b) he is so cheap because well he heas no money really.

I am the guy who always preaches about doing it right the first time, and I always do (everything I have put on my car so far is QUALITY) but before I put the money down I always rethink it about 50 times, before my wallet gets much lighter

[Tom Vaught]

Originally Posted by andrewT

I hope thats not directed at me. My buddy with a fox body has been doing everything twice because a) he is in a rush and b) he is so cheap because well he heas no money really.

I am the guy who always preaches about doing it right the first time, and I always do (everything I have put on my car so far is QUALITY) but before I put the money down I always rethink it about 50 times, before my wallet gets much lighter

In no way was directed at you.

The average inexperienced guy is different from the "Guy who is in a Rush" or the "Cheap Guy". Sometimes you get both (like your buddy) in one package.

The difference is: over time the inexperienced guy will learn and will make sound decisions. The "Guy who is in a Rush" or the "Cheap Guy" will not change over time.

Tom Vaught

[andrewT]

Originally Posted by Tom Vaught

In no way was directed at you.

The average inexperienced guy is different from the "Guy who is in a Rush" or the "Cheap Guy". Sometimes you get both (like your buddy) in one package.

The difference is: over time the inexperienced guy will learn and will make sound decisions. The "Guy who is in a Rush" or the "Cheap Guy" will not change over time.

Tom Vaught

Np Tom. regardless I knew you were just giving advice. My buddies all rip on me for being stingy and thinking through my purchases like mad, but I think its a decent quality.

[ponjohn]

IF you're admitting to driving it in the rain stop right there, get a posi.

If you can guarantee no wet weather driving run a spool.