Final drive

[James Morse]

My 85 5.0 Mustang GT had 2.73 isn't that weird? But you could start in 2nd and stay in 2nd up to 70mph which was kind of cool.
Seems like a totally non-performance ratio to put in a performance car.
Kind wish I had that car now it had the T-tops.

 

[Blmpkn]

Whoever ordered that car originally was worried about highway mileage is my guess.

 

[RonD]

V8 power, light body and frame, 3.70 1st gear, smaller diameter tires
Not made for towing, lol
2.73 rear axle ratio was made/used for top speed

Not sure it would be for MPG with a V8
4cyl was available for that

 

[James Morse]

yeah they had the 4-cyl turbo too but it wasn't real popular it was pricey. different model name.

I can't remember what my mileage was I don't think it was great even with logey final drive

had a couple Fiestas (79 and 80 I think) they got great mileage and easy to work on, built like a tinkertoy
I won regional in SCAA ITC in one many many years ago
didn't win a single race usually but I showed for every race that gave me the points it was a surprise to me for sure
so that says something for just showing up and finishing
I raced at NH speedway when it was just barely finished that's how long ago.

 

[19Walt93]

An 85 T5 had a 3.55 low gear, 3.55x 2.73= 9.6915 multiplication. A close ratio top loader had about a 2.32 low, 9.6915/ 2.32= 4.17, so your 85 GT with a 2.73 axle would launch like a top loader with a 4.17 rear. 5th gear was .67 so your 2.73's would have acted like a 1.89 gear. My old boss has a 79 Mustang Pace car that I worked on last year. When I checked the rear end I hoped to see 3.08's but figured it would have 2.73's. Nope, 2.47's behind a 139 hp 302. It's a barking dog. 80 and 81 Mustangs and Fairmonts with the 255, the only available V8, came with 2.26 gears. The only transmission was a C4 so they at least had the advantage of a torque convertor but they weren't a ball of fire.

 

[Blmpkn]

V8 power, light body and frame, 3.70 1st gear, smaller diameter tires
Not made for towing, lol
2.73 rear axle ratio was made/used for top speed

Not sure it would be for MPG with a V8
4cyl was available for that

I have a couple old v8 cars with 2.43 gears, definitely not for top speed in those applications

 

[Josh B]

That 60's Chevy 2 speed, was it HydraGlide, went in all the cheap ones, I had one behind a 283 in a 64 Impala, later put a smaller 6 in it, it always did fairly well.

They wound up scraping all those ones up they could to use in race cars, only had one shift to make, and a 1/4 mile to do it in, ain't got time for too many shifts in that

 

[rusty ol ranger]

My 77 LTD II has an FMX with a 2.46:1 1st and s 2.50 rear and pry weighs what 2 foxbodies do. Or pretty close.

Granted its a 351w but still. Wouldnt hit 3rd till 85-90 at WOT.

So its not suprising a fox even with 2.73's runs hard.

 

[Snoranger]

My buddy had an ‘87 GT with 2.73s… that thing wasn’t even starting to break a sweat hitting triple digits but it took a week and a half to get there.

My ‘94 Cobra has 3.08s, I would regularly cruise at 100-110 when it was my daily driver. I had it up to 155 and she still had a lot more in her… I was quickly running out of real estate and had to back it down to a reasonable speed.

 

[Blmpkn]

My buddy had an ‘87 GT with 2.73s… that thing wasn’t even starting to break a sweat hitting triple digits but it took a week and a half to get there.

My ‘94 Cobra has 3.08s, I would regularly cruise at 100-110 when it was my daily driver. I had it up to 155 and she still had a lot more in her… I was quickly running out of real estate and had to back it down to a reasonable speed.

Going that fast is scary AF.

Fastest I've been is 138 in my old outback, and I was NOT a fan lol.

 

[19Walt93]

My Cobra II has 3.55 gears behind a T5 and would turn 13.8 at 102 mph in the quarter- in 4th gear at about 5500 rpms. Mathematically it should be capable of around 130 mph but I like having a drivers license and wasting money on fines would piss me off. With the 3.55's and a 3.35 low it has 11.8925 multiplication, the same as a close ratio top loader with a 5.13 rear. I would launch at idle and roll into the throttle to keep traction, I'd have to shift to 2nd before the throttle hit the floor because I was out of RPMs.

 

[ekrampitzjr]

I have a couple old v8 cars with 2.43 gears, definitely not for top speed in those applications

The 2.73 rear end with a 5.0 described in the OP might have been for top speed. Keep in mind a lot of police-package Mustangs were sold in the 1980s as high-speed pursuit/interception cars because the regular Crown Vics and other sedans were too heavy for the underpowered V-8s of the day for that purpose. Ditto for police-package Camaros then. James Morse might have had a gussied-up version of the cop-powertrain Mustang. That would be something today.

In Virginia these days getting busted for anything above 100 mph generally means an automatic trip to jail.

 

[Chapap]

Top gear (the real version) had a car one episode. Clarkson did 0-100 in one gear.

 

[Blmpkn]

Top gear (the real version) had a car one episode. Clarkson did 0-100 in one gear.

It was a zr1 corvette in 5th

 

[19Walt93]

The 2.73 rear end with a 5.0 described in the OP might have been for top speed. Keep in mind a lot of police-package Mustangs were sold in the 1980s as high-speed pursuit/interception cars because the regular Crown Vics and other sedans were too heavy for the underpowered V-8s of the day for that purpose. Ditto for police-package Camaros then. James Morse might have had a gussied-up version of the cop-powertrain Mustang. That would be something today.

In Virginia these days getting busted for anything above 100 mph generally means an automatic trip to jail.

I had forgotten but there was a recall on cop Mustangs because some got built with 3.08's and wouldn't go over about 130 mph so we swapped in 2.73's.