Help on Gears Please

L

LIL QIK

Registered User
Hey guys......

Well......my factory 2.73 is getting a lot of slack in it.........so I'm fixing to go ahead and replace the gears.....

Was hoping that someone might have a clue or some experience as to which gear would work well with the five speed in the SC's......I would really like to keep the 2.73 but can't find a high performance replacement.......so I figure that I might as well step it up a little........problem is that I haven't met anyone with the 3.55's in the five speed and not sure if the 3.27's will give me a big enough difference from the existing 2.73's.

So....was looking for some response out there from some of you that may have tried the 3.55's with a five speed. Please give me an idea of how streetable the car is with these gears........

Also.........if any of you know of where I may be able to find some 2.73's new for our rear end......then that would be appreciated as well.

Thanks....Dave
 
3.27's

LIL QIK said:
not sure if the 3.27's will give me a big enough difference from the existing 2.73's.
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The 3.27's are a GREAT gear for a 5-spd car. HUGE difference in performance. Is this primarily a street car, or a HOT strip car? You didn't mention if you have an early or late model 5-spd? The late model 5-spd has closer gear spacing, and will extend 1st & 2nd gear.

68COUGAR
 
This is my daily driver but am constantly running into people that want to play...and I'm a pretty spirited driver even when not playing....I'm currently trying to the build the SC to around 400 at the wheels and hope to keep it as my daily driver.....

I have the 89 model......and from what I understand or found on the internet......the gears are

1st = 3.75
2nd = 2.32
3rd = 1.43
4th = 1
5th = .75

If I'm mistaken on these ratio's please correct me.....there's no telling how reliable the source was.

Anyway......I've got a speed calculator 1st gear shift only suffers about 10 mph loss between the 2.73 and the 3.55 which doesn't bother me too much.....

But the rest of the gears lose 20 mph and more when going to the 3.55 which does bother me a little. I've driven the SC with a 3.27 but his car was a 94......so by what you're saying......he probably had different ratio's than me. So I really can't use his car to compare. But I did like the way his pulled.
 
LIL QIK said:
This is my daily driver but am constantly running into people that want to play...and I'm a pretty spirited driver even when not playing....I'm currently trying to the build the SC to around 400 at the wheels and hope to keep it as my daily driver.....

I have the 89 model......and from what I understand or found on the internet......the gears are

1st = 3.75
2nd = 2.32
3rd = 1.43
4th = 1
5th = .75

If I'm mistaken on these ratio's please correct me.....there's no telling how reliable the source was.

Anyway......I've got a speed calculator 1st gear shift only suffers about 10 mph loss between the 2.73 and the 3.55 which doesn't bother me too much.....

But the rest of the gears lose 20 mph and more when going to the 3.55 which does bother me a little. I've driven the SC with a 3.27 but his car was a 94......so by what you're saying......he probably had different ratio's than me. So I really can't use his car to compare. But I did like the way his pulled.
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I have an '89 5-spd XR-7. I changed my 2.73's to 3.27's, with the early 5-spd. When I was racing, 1st. gear was basically, Dump the clutch on green, & have to shift again into 2nd. within 5 seconds.

A couple years later, I switched to a late model 5-spd. The late model gear ratios extend 1st & 2nd gear. It's MUCH easier to drive on the street & track with a late model M5R2 & 3.27's.

68COUGAR
 
Your gear figures are correct. I have a 94 5 gear and I also have a Ford Service Manual and the gearing you listed for each gear is exactly as in my manual.
Here is an excellant gear/speed calculator that I am currently using as I also need gears. http://www.f-body.org/gears/
The idiots who decided on 2.73's in this car deserve a fate worse than death IMO.
Reguardless of the low first gear the car suffers badly from these turnpike gears. More like Bonneville Salt Flats gears!
These car have a narrow power band. With those tall gears it really is no fun to drive.
Everyone seems to love the 3.27's in the stick cars. And I also may go with them. But I am pondering 3.55's.
As it is now for any use, even highway, the car takes too long to get up to speeds. I had mine out in the west desert here and with my GPS, I shifted out of fourth gear at 4300 rpm, my GPS was reading 128 MPH!! Did this twice as I was doing some calculating. We have a lot of lonely roads out here but to get the top speed on this car I think I might need about 4 miles of flat and no cops!
Having drag raced a 94 5.0 Mustang for 4 years(100 passes a year), street/strip car, I can tell you that the best thing I did for it was adding 3.73's in it. Being it was NA, I really wish I had gone 4.10's! But I ran slicks and did a lot of serious racing with it. The 3.73's made it a better city car and really did nothing to hurt it on the highway. Heck, I had it up to 138MPH in 5th gear on my GPS and had to shut down. Probably would have gone about 145 or more. Remember, it also got up there quicker than if it had 3.08's! This is with about 260 RWHP and was at about 5000 ft elevation so I was down about 60-75 hp!! I can also tell you most road racers(Silver State in Nevada) run 3.55's and no less than 3.27's. You still need to get up to speed quicker. 2.73's went out the door with the old cop cars and big cubic inch mills. People out at Bonneville dont even run 2.73's with 600 and up HP engines! 3.08's or better.
Our cars would be ok with 2.73's with about 400 RWHP!
If I go 3.55, I will get all the stuff from MN12 site to stabilize the IRS so I could put some soft skins on and launch this Tird.
Your mileage will suffer but you will enjoy driving it more, it will be quicker, about like adding 30-40 hp. You will be able to stay in the power band around town easier, so if you do have to run a yellow light, you wont have to downshift to get the Tird going.
If this car had a T-5 trans, I would be going 3.73s all the way. But the first gear in this truck transmission governs the decision.
I am leaning 3.55 for the sake, if I go to all the trouble to change em, I want some bang for my buck. Any choice will make it an all around better car. I was hoping someone would chime in that is running 3.55's.
Take care, Danny from Utah;)
 
I went from 2.73's to 3.27's and didn't like them 1st gear was too short. I have since changed to 3.08's and I like them the best nice low grunt and revs nice on the hwy.

If you like the 3.27's just change the whole pumpkin from an auto car and you don't have to get the gears set up just change the pumkin and go.
 
Yea...........I'm leaning toward the 3.55's.......but that would almost be like running a 5.13 with my six speed. I've been talking to Forte's about getting a six speed for this thing............but will probably weight until I get to the 400+ mark at the wheels.

Thanks for the input guys.......
 
This has been the subject of much debate.

I can offer the following. 3.55's are about ideal for drag racing an SC. Only problem is 1st gear will suck no matter what. You will be crossing the finish line above 5000rpm which is nice, but good luck hooking up in 1st and like Cougar said, first gear comes awful quick - datalogged to be 1.5 seconds in my car at 400rwhp. :eek: 2nd gear isn't much better (under 3 seconds).

So, I am going to run 2.73's for my next buildup. A radical cam and 2.73's is a little bogus on the initial roll out on the street, but once you are moving they kick butt really. You will find that you can't use 5th at any less than 70mph though. :D

IMO, 3.27's suck. I hate em. But then again I like drag racing. It's just the part about crossing the finish line at 4800rpm that I hate.

More than likely it's not so much the gears that are loose anyway. I'd be suspicious of other parts in the driveline and diff bushings as well. Did you price the 2.73's new from Ford?
 
Ideally I'd like to see a 6spd with a 2.95 first gear. Then I'd run 3.73's or 4.10's out back and have the cruise gear as well. :D
 
shotbirdsc said:
I went from 2.73's to 3.27's and didn't like them 1st gear was too short. I have since changed to 3.08's and I like them the best nice low grunt and revs nice on the hwy.

If you like the 3.27's just change the whole pumpkin from an auto car and you don't have to get the gears set up just change the pumkin and go.
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Hell.....if you ask me......the 1st gear is just too short no matter what......even with my 2.73.......but I think that's mainly because this motor doesn't use any rmp's..........

But I'm trying to change that with my motor new build......I'm trying to build the next motor to make hp up to 6200-6500.

It'd be nice if someone making 350+ rwhp at something above 5800 could chime in.......give me a clue as to what they're running.
 
Man........it's like 3 post happened while I was writing that last one........lol.....

Dave.....I haven't priced the new gears from Ford........it actually didn't even cross my mind. I actually like my 2.73 with this tranny.......makes it nice to pass someone and not have to change gears.......

I've often thought that if I just had the power and rpm's to go with it.........that this setup wouldn't be that bad. I've done the calculations........and the five speed that I'm currently using with 2.73's is the same as having my LS1 6 speed with 4.10's in first and final overdrive.....so it's really not that bad.........it just needs the power and rpm's to go with it.

But I'm pretty sure it's the rear end.......when I changed the clutch.....I noticed a lot of slack in the pinion.........I'm really surprised it's not singing to me yet.......lol
 
Ok.........this is going to sound bad.........but what rear end do we have in our cars.........I just assumed it was an 8.8
 
Since we are talking gears and tranny, anyone done or heard of a T-5,Tremec TKO or T-56 going into to a SC? Just curious how much trouble. Easier to get parts for, they take more torque, esp the T56 and as XR7 Dave eluded to, many more possibilities!
 
DMZ said:
Since we are talking gears and tranny, anyone done or heard of a T-5,Tremec TKO or T-56 going into to a SC? Just curious how much trouble. Easier to get parts for, they take more torque, esp the T56 and as XR7 Dave eluded to, many more possibilities!
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Well like I said........I've been talking to Forte's about getting me a six speed. I wanted the LS1 six speed being that I like the ratios in that tranny better and our cars are already using the same throw out bearing as the LS1's. Unfortunately.......all of the T-56 that will bolt to the 3.8 use different gears than I want and they are also a different clutch style.

Someone had told me that McLeod or Lakewood was making a bell housing to adapt LS1 T56's to the 5.0......if so........that's the bell housing I need to find because I would like to keep the current TOB setup. Plus like I said.......I like the LS1 ratios better than the Cobra ratio's.

We'll see how that all goes.
 
XR7 Dave said:
This has been the subject of much debate.

I can offer the following. 3.55's are about ideal for drag racing an SC. Only problem is 1st gear will suck no matter what. You will be crossing the finish line above 5000rpm which is nice, but good luck hooking up in 1st and like Cougar said, first gear comes awful quick - datalogged to be 1.5 seconds in my car at 400rwhp. :eek: 2nd gear isn't much better (under 3 seconds).

So, I am going to run 2.73's for my next buildup. A radical cam and 2.73's is a little bogus on the initial roll out on the street, but once you are moving they kick butt really. You will find that you can't use 5th at any less than 70mph though. :D

IMO, 3.27's suck. I hate em. But then again I like drag racing. It's just the part about crossing the finish line at 4800rpm that I hate.

More than likely it's not so much the gears that are loose anyway. I'd be suspicious of other parts in the driveline and diff bushings as well. Did you price the 2.73's new from Ford?
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Hey Dave,

Do you feel that 3.73's are a decent upgrade for an AOD car? Do you have any personal experience? I am left with the question now what to do with my gears and I'm lost. :confused:
 
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