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Junior Charter Member
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Discussion Starter · #1 ·
Ok IRS here we come...

I found a 97 Lincoln Mark VIII donor $400 for the whole rear end... in good shape, car was hit in the front, still running.

Before I make the drive to pick it up, (he has no idea about the numbers on the case, or is just lazy and doesn't wanna look)
I'm assuming It'll be non-posi, since from my readings most lincoln's are non-posi.
I'll probly be changing the gears to 3.55 anyhow so ratio isn't that much of a deal

3 questions:
How hard and how much!??!
1st How hard is it to change out the gearset/diff in the pumpkin to posi?

2nd how much does the posi rear "guts" cost?
I see gearsets are around $200 to change the ratio.

3rd is the spacing on the lincoln's 4.5" or 4.25"? having the 4.5 spacing might be an added bonus!

thanks!
 

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It's a pretty simple process to change out the carrier to a tracklock unit, but why go to the expense and hassle? You should be able to find a posi unit for the same or less money than the $400 they want for this one.
Either way, changing gears is going to cost the same so that part is a wash.

All the Lincolns and Tbirds are 4.25" spacing and will need to be redrilled or you can buy Cobra hubs and replace the existing hubs but that brings other issues also due to the larger hub center. Either way you will need to make decisions based on how you plan to build your car.
 

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Runs with scissors!
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I'm with BS, finding an IRS unit with the gears you want and POSI isn't that difficult. The wrecking yard I went to in Denver had almost a dozen 8.8" IRS "stubs" laying in a row, I just looked at all the tags and picked the one I wanted (3.27 POSI)
 

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$400 sounds about right.

I got my stuff from Decy, a member on the forum.

He gave me the posi and I had someone locally install it.

Stu Spencer will redrill your hubs.

I would contact both of them through the forum, might save you a lot of work and head scratching!
 

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BS:
Are you sure all Licolns are 4.25 spacing?
I know the 'Birds are.
I have a Lincoln front Rotor assembly and it is most definitely 4.50 inch spacing.
Paul M.
 

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Junior Charter Member
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Discussion Starter · #7 ·
well if its not a "locker" I'll pass on it... $400 for a posi unit seems kinda pricey if I can hold out for one the "L" code. do any lincoln mark8 have the posi? the ratio and locker code is on the pumpkin right?
 

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To my knowledge. The MK8 did not have a posi in any of them.

The only way to have the alloy pumpkin and a posi is to get the guts from a Tbird 8.8 and put them into the lincoln pumpkin.
 

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BS is right about the bolt circle on the Lincoln hubs but I wouldn't bother redrilling or changing them to 4.5". Just buy the rear wheels with 4.25" bolt circle. It's not like you are going to interchange the wheels front to back, since they are different widths, and noone is going to be able to tell difference anyway.
Tork

I have the GT-40 style wheels with metric lug nuts in the rear (5 x 4.25") and SAE lug nuts in the front (5 x 4.5").

[ July 02, 2007, 02:56 PM: Message edited by: Tork ]
 

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Originally posted by Tork:
BS is right about the bolt circle on the Lincoln hubs but I wouldn't bother redrilling or changing them to 4.5". Just buy the rear wheels with 4.25" bolt circle. It's not like you are going to interchange the wheels front to back, since they are different widths, and noone is going to be able to tell difference anyway.
Tork
Generally, Aftermarket wheels that are sized and styled for use on Cobras come in 5 on 4.5" or 5 on 4.75" bolt circles. There are custom wheels in the 5 on 4.25 bolt circle, but I don't think there are any Halibrand type wheels available in the 5 on 4.25 bolt circle. Additionally, factory TBirds used metric wheel studs, and they will need to be changed out to SAE studs to be compatable with the lug nuts supplied with most custom wheels. John

Added: The wheel studs that FFR supplies for the IRS are actually SN95 front wheel studs. There is nothing wrong with them, except if you later want to change to an aftermarket stud for increased length or strength, And your hubs are drilled for the FFR studs, the only ones that will fit are made by ARP, and they sell for $39.75 per set of 5. If you drill your hubs for FOX type ARP studs, they sell for around $11.00 for 5. BTW, the only place to buy the ARP SN95 wheel studs is Maximum Motorsports.

[ July 02, 2007, 01:25 PM: Message edited by: J Persons ]
 

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The other problem is that the studs are metric.

FFR supplies 10 studs for the redrilling.

Read and re read the back section of the manual on compitble parts.

I have the best setup and it was real easy sourcing parts cheaply and getting hubs redrilled.
 

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i took a mark VIII aluminum pumpkin and put a torsen limited slip in it, saves weight (82 vs 57 lbs) and the torsen rocks in this car.

the aluminum pumpkin is strong- i lost a front differential mounting bolt and with race tires at WOT in 2nd gear, there was enough torque to twist the pumpkin so the passenger side CV joint escaped, twisted the heck out of the rear mounting ears and tore the front subframe at the remaining bolt up like a sardine can. the diff is fine.

james
 

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iBuild
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SoundEQ, not sure how far you were planning to drive, but I found a guy last year who is into rebuilding supercoupes. I should still have his contact information, I will look tonight, I know he had 3 or 4 more cars in his yard to part out.

_Scott
 

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Junior Charter Member
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Discussion Starter · #14 ·
I suppose: YAH give me his contact info!
I was going to drive all the way out to LONG GUYLAND!

I (finally) found a t-bird complete rear, and the guy at the place was nice enough say he'd let me exchange any pumpkin he had to get the right ratio/posi to get what I want... I'm thinking 3.27 (1st choice) or a 3.08 if I can't find a 3.27
But ANYWHERE in NJ would be closer, then I don't need to drive through manhattan.
 

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FYI, I have seen empty aluminum MK8/Cobra IRS differential cases on Ebay for about $120. You could put a torsen in one of those.....
 

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Discussion Starter · #16 ·
Ok update...
Drove WAAAYYY out on long island NY, but got me a rear!

93' t-bird rear... 8.8 3.27 LOCKER gears! whole rear end assembly for $250... Not bad!
WOW lots of leftovers! I should have brought some tools and just taken the pumpkin, axles, and spindles/knuckles/brakes...
Thanks for everyone's help!
 

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Now put the guts of what you have in a lincoln mk8 alloy rear and you will have 3.27, 5 lug and posi.

The alloy rears clean up like new.
 

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Discussion Starter · #18 ·
yah my rear pumpin is a rust bucket... chiped off about a 1/8 of rust, the CV and inside the pumpkin looks brand new. Yah perhaps I can scoop up a lincoln carrier, since that'll be easier to clean.

the nut on the end of the spindle, I'm never gonna get that off without an impact wrench right?

Time to invest in some tools, or make some friends at the local shop!
 

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the axle nut is 36mm deep. try lots of leverage, then when that doesnt work, i think its safe to heat it up.
 

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What Ophitoxamia said. I put the wheel back on, and slid some black pipe over my 1/2 inch breaker bar. From here it's easy off.

Iggy
 
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