Let's not forget, CAFE and emission reg's were something the auto industry was struggling with - even back then. Consider all the 2.73/2.77 geared cars as sacrificial lambs towards that cause. Actually, I think most 5.0 Mustangs came equipped with 2.73 gears too. The difference being that they also usually came with a third pedal and the standardized "good" motor 5.0 in a lighter package. The only reason I can see GM continuing with LG4/L03 engines in their top Camaro/Firebirds when L69/LB9/B2L's were available was just utter cheapskatery.

Jason, are you sure that your TA has a 2.77 rear. If so, it has an Aussie BW 9 bolt rear end, which is kind of a cool thing to have.

 

Unless it ever needs service parts, or you want to change the ratio.

 

Uh, yup I counted 9 bolts when I changed the fluid on it And while the RPO sheet has dissappeared from the console, I got the invoice from PHS, and there is no perf axle option

Drew is right, its cool until you wanna change the ratio. Assuming I keep it, I'm REALLY considering swapping in my spare 3.73 L69 10 bolt for the hell of it, even though its probably more aggressive than a stock peanut LB9 needs. At least it'll wake it up!!!

As the same point, it would probably make my 88 TA even more amusing than it is already!

 

The 3.73 is an '83, right? Keep in mind that the brake lines on '83 and down are SAE and '84 and up metric. Save yourself the headache and FedEx that rear end to me, for my Crossfire.

 

Since we are on the subject, on a stock car, isnt a 10 bolt good enough? What is the difference between the two type of positrac used?

I am really interested in the types of LSD/Posi used in my 85 10 bolt. When the rear end is jacked up and slowly turn the rear tires the other tires spins opposite, yet is it a posi and works very well.

 

In theory, a 9 bolt is stronger. For certain years, 86-87 specifically, it seems all the uber-powerful TPI cars (I use that term jokingly....) used the more durable 9 bolt.

The problem is, NO ONE makes new parts for them. A 10 bolt is totally fine for a stock, un-abused car IMO...

 

Cerberus, don't fret over the rear end. I would run it till it broke, then worry about replacing it. If you can jack the car up, and the tires spin in opposite directions, you have an open diff. Pull the rear cover and check it out. You will see that you have no clutch pack in that unit. An open rear actually promotes longevity, too. It will not hold incoming torque and supply it to both wheels. You will have a spinning wheel to relieve the pressure on the diff. As to gear ratios, my old pony had the standard 2.73 rear gear, too. A 2.73 car wasn't much different that a 3.08 on those cars, except that a 3.08 car would redline 4th gear and require a shift to 5th for top speed. The 2.73 cars would top out at 5200-5400 in 4th at something just shy of 140mph if you held the pedal to the floormat long enough. Generally, the 2.73 Stangs were good for about 40mph in 1st, nearly 80mph in 2nd, about 120mph in 3rd, and ran out to top speed in 4th. Most practically, the 2.73 cars could sprint to 125-130mph or so fairly easily, and that was enough in most cases to seal a victory in most street encounters. The GM cars just wouldn't deliver the numbers seen in period magazine tests on the street, while the 5.0 would. Maybe GM was supplying more "ringers" to the mags than Ford. I clearly remember anticipating each new GM killer car hitting the streets year to year. With the L69 and TPI both, I was prepared for a hard fought scrap for victory. Instead, we found the street L69's to be generally stuck with auto transmissions in most cases, and unable to challenge the Ford's dominance. The TPI cars were, sadly, laughable. The 305 TPI could not defend itself on the street. I am convinced to this day, that an L69 5speed car was a better runner than the 305 TPI in any trim. I approached my first TPI 305 with real fear of getting whipped in my 5.0. It was an 85 WS6 TA that belonged to an aquaintance of mine. Instead, quite to my surprise, I beat the living Hell out of him. I had a similar experience riding shotgun in an 85 5.0 Capri GS against a new 86 TA with a "chip" running out of the local Pontiac store. No contest in either case. Thanks, Oldtimer.

 

It's positrac for sure, it operates as it should, different LSD will operate differently. It will positively LOCK if one tire spins.
Yesterday, right tire (passenger)in water left tire on dry and after a few rotations the dry tire spins too. It's a locker type.
I believe it's a gov lok, I'm 100% stock so I really don't have much to worry about.

This interests me as its a g80 code type posi in 1985. I have been told that the system used in 85 was designed just that way.
Depending on spring weights used in the carrier is how it will lock. I think this posi had three different springs that could used.

I think I will start a separate thread and post video of it, then take pics of it when I change fluid.

Not worried. I find it funny it acts as designed. Depending on the clutch and locking mechanism is how the unit will engage.

 

While it's true that Mustang 5.0's of the time would eviscerate an LU5/LG4/L03/peanut cammed LB9, in a straight line, I do think that the right combo 3rd gens could more than hold their own with them. And I speak from first hand experience. The L69 5 speeds gave 3rd gens instant parity with Mustang in '83 and '84 in a straight line. And the later dual cat, LB9, 5 speeds and L98's really had no fear of 5.0 Mustangs.

Speaking of 5.0 Mustangs, they weren't all equal. There could be a 1-1.5 second difference in the 1/4 mile between say a Mustang GT convertible, automatic, 2.73 and an LX sedan, 5 speed, 3.08. And of course, how many 5.0 Mustangs reamained stock for long on the street? Virtually all of them had the "free mods" at least.

 

I think the 85 IROC with 342 and TPI such as mine would give a mustang a run for its money. I dont think it would handle an 1/8 mile race but for sure it would pull past in a full 1/4.

1st gear in my car is nothing more than smoke and two long patches. Even from a roll.

 

It'd be a good race. Stock for stock, the "right" 1985 Mustang GT with a good driver might edge it out by a tenth or two.

 

Between ratechh and 9bolt.com pretty much everything is available. Bearings re available at a parts store.

Spicer still makes this axle today for other applications and all the parts are still made new today. Its just a matter of having them imported. Posi cones are available too. My 3.70s are aftermarket gears... not any more expensive than new 10 bolt gears.

The problem is that you can end up with a rear end that's got a lot of money in it that will still break in a modded car. If it was as tough as a 9 inch it wouldn't matter.

 

Good luck getting those parts from Australia as quickly as you can get parts for almost anything else... Figure 10 bolt gears, limited slip carriers (you have your choice of several), and service parts can be had in about 3 days if you even have to order them.

I'm just not a fan of the 9 bolt. I've had half a dozen of them, and in general I just think they're a pain in the ***.

 

I agree. I wish I had just started with a 10-bolt but I'm down this path now due to availability, necessity, and budgets at different times, and Im happy with what I have. The day it breaks will be a little frustrating, though.

I definitely wouldn't advocate going out and finding a 9-bolt. But parts are there even if not all that conveniently, and it is a nice diff if it's in good working order.

 

It was an interesting time. Gas prices were down from record levels in the early '80s. The economy was getting strong again. And, as a consequence, performance was coming back into vogue, on all sorts of levels.

There was a lot going on. For new cars, the IROC and Trans Am with the L69 or LB9, the Mustang GT and Capri with the new 210 horse roller cam 5.0, and, of course, the Corvette with the 5.7 liter TPI had the most street cred. Of these, I'd say the 5.0 Fords had the edge. Not only were they a little quicker out of the box than the TPI/L69 F-bodies, but they were a lot cheaper. There was probably a $3k difference between a stripper Mustang GT and a TPI IROC-Z. That was a lot of money back in then!

I recall the L69 Monte Carlo SS's still having a lot of respect on the street as one of the first "new" muscle cars. Its siblings, the 307 cid 442s and pre-intercooled Regal turbos, were generally considered inferior, though the '85 SFI turbo Regal made some serious power gains and those in the know started to take notice.

Imports were gaining credibility, with cars like the sophisticated Mark II Supra, the refined RX-7 GSE, and the fast 300ZX Turbo. But these weren't yet on the radar of America's young people, and mostly appealed to yuppies. That would change in a few short years of course but, in the mid-80s, these cars were a non-issue on the street.

We were also in the early pocket rocket era with cars like the VW GTI, Honda Civic and CRX Si, Dodge Colt GTS Turbo, and Dodge Omini GLH and Shelby Charger. The latter three were credible stoplight racers, as were lesser known but surprisingly quick cars like the Citation X-11 and 1.8 liter turbo J-cars (Skyhawk T-Type and Sunbird GT). They also got good mileage and were fun to drive, a concept the auto industry seemed to have lost until very recently.

Affluent Baby Boomers were igniting the first muscle car investment boom but, for the most part, '60s muscle cars were plentiful and roaming the streets as often-modified racers. With big engines, and no computer or emission constraints, these cars were easily the kings of the street racing circuit back in those days.

New mid '80s cars did not compete with them for top street honors until the late 1980s, when the 5.0 EFI Mustang and '86-87 intercooled Regal craze hit. In 1985, computer controlled engines were still in their infancy and there weren't a lot of parts for them, or any widespread understanding of how to modify them. Aside from ripping out their small displacement engines and installing a 350 or what have you, it was hard to get serious quarter mile times out of them. And with '60s muscle cars and late '70s F-Bodies still cheap, plentiful, and much easier to modify, there was no reason to do this anyway.

Overall, it was a very interesting time for gearheads! It doesn't get the attention that other hot rod eras do, but it certainly should.

 

Good points.


It was a pretty interesting time for car guys. I mean just from Chevy, you could choose from Corvette, Camaro, Monte Carlo SS, X-11, Z24, am I missing any?

Also true, is that although Camaro and Mustang were direct competitors, you could get a 5.0 Mustang for a whole bunch less than a top engined 3rd gen. Thousands less.

 

curious, how much less?

 

A Mustang GT's base MSRP was $9,885, and it came with all the performance goodies, except for the traction lock rear axle I think. A base Z28 was $11,060 but to that you had to add the IROC package ($659), LB9 motor ($680), and mandatory automatic transmission ($395). Most added the 4-wheel disc brakes too ($179).

So, adding all that together, a base LB9 IROC came to $12,973, or about $3,100 more than a Mustang GT. Plugging that into the inflation calculator, that's a difference of about $6,200 in today's dollars. I think most would agree that is pretty significant.

 

Whos your friend lol i been on that site since 08 back when i had my 80 notchback and 82 GT


i loved my mustangs they handeled like *** but were quick my 82 gt was mostly stock but had a 5 speed instead of 4 and a 4 barrel instead of the stock 2 barrel and i used to rimp on my buddys iroc all the time but like i said arround turns he would totaly lose me....than again i ran skinnies on it

 

When I bought my '89 IROC, I had intended it to be my daily driver. But I still hadn't sold '84 GLH yet, and found myself continuing to to take that to work. When winter came, I realized that the IROC would never see snow, so I drove the GLH another 2 years. When it's reliability became a problem I knew that a new new daily driver would be needed, and almost ordered a new 5.0 Mustang LX notch. Had I not gotten an unbelievable deal on a 900 mile VW Corrado G60, I'd bet that I still would have owned that Mustang.

 

Charlie,

How was the Corrado? I always liked those when I was yonger...I remember when they put the VR6 in them, I lusted after one. I've never driven one, but they've always seemed like seriously cool cars to me...

 

It was a great car. The VR6 was much nicer than the G60, IMO though. Mine was yellow with black leatherette and cloth Recaros. Best seats ever. I remember one spring, hopping into my IROC after driving my Corrado all winter. The IROC's seats felt like broken lawn chairs. They were pretty expensive cars - like over $20K, which was a buttload of money back then for a VW. I got to meet an employee of VW of America and we started talking. I told him I needed a new car and he said that VW's regional HQ in Lincolnshire, Illinois had a bunch of leftover, yellow '90 G60s. (Am I the only guy that likes yellow? )

Anyway, he was driving one of them. He said he needed it to go to a meeting in Detroit, but I could have it for $12K after that, (it had 900 miles on it when I got it). Sold!

It was great car. Handled great, braked great, communicative steering, adequate power, unbelievably stable at high speeds, had that neat active rear spoiler. Bend over if something broke however. My wife hated the color of that car as much as she hates the color of my new IROC. Oh well......



Here's me and the Corrado in the paddock at Blackhawk Farms, in northern Illinois, circa 1991.




Oh, before anyone starts - THAT IS NOT A PINK SHIRT!

 

Yeah, my wife doesn't dig yellow...or pink shirts for that matter, but I digress

She also dislikes my father's Sunset Orange Formula, but as she's said to me before when it comes to car decisions, "its your car...what do I care?" Good answer

She does really dig the blue of the TA and the grey of the IROC...then again, the blue TA has received more compliments than any car I've owned...even more than the IROC. That damn silver chicken with all the silver trim...people just love it. Park the IROC and the TA next to each other at a cruise night, and the TA gets more attention.

Go figure...its probably because you simply see more IROCs around. Personally, the older I get, the more I appreciate the cleaner shape of the TA, and I love pop up headlights.

 

I found this in an old 1985 AUTO-X mag. Dang! The GLH-S (goes like hell-s'more) is fast 0-60 in 6.95 seconds and 14.9 in the 1/4 mile.