4.11 or 3.73's and sohc or dohc

T-Bone · 01-31-2000, 06:03 PM

Hey Guys, Thanks for all of your help recently. I've got a couple more questions for you now.
First, a friend of mine, who is a mechanic, told me I should go with 4.11's. I've noticed that most of the GT's have 3.73's and the Cobra's have 4.11's. How much will the two different gears change low end and high end performance? I want to make the right decision and get the gears that will suit me best. I guess I want to get up and go faster. I don't really care if the top speed is decreased that much. What will the top speed be with both gears, if anybody knows?
Second, the mechanic also told me that he's pretty sure it's a DOHC, by looking at it. I'm not sure, but I fiqured it was SOHC since thats what most or all of the 96' GT's seem to be. I have no owners manual to refer to for the specs. How can I find this out for sure?

Thanks in advance!
T-Bone

Hammer · 01-31-2000, 09:01 PM

Well, any mod motored GT is SOHC stock, no matter how you cut it. Since I haven't stuck my nose under the hood of a Cobra very often, I couldn't tell you just what the cosmetic differences might be. (Athough I do think that the intake is noticeably different).
So unless whoever owned the car before you put an awesome amount of money into this vehicle, I doubt it's DOHC.

As far as gears,
If you're staying light to moderately modded for now, run a 5-speed, and use this thing as a daily driver, 3.73s are for you. Plenty seat of the pants get up and go while retaining most of your top end and gas mileage. The ratio fits the power band of an SOHC mod motor to a T. There has been some debate about some automatic users going to 4.11s without major mods, but I have yet to see one in actual use to have a reliable comment for autos. In my opinion, you might just be cutting off a little too much streetability with 4.11s.
One more thing, Be sure to get a shifter for those gears... You won't regret it!

------------------
98 GT
Dyno-Max cat-back exhaust, 3.73 gears, Steeda shifter, Ford Motorsport Underdrive pullies, 87mm MAF and Roush cold air kit...

T-Bone · 01-31-2000, 09:17 PM

cool, thanks again Hammer!

Dynamite69 · 02-01-2000, 01:45 AM

Look at the intake, if there is a big Cobra on it, then its a DOHC.. also look at the passenger side valve cover (for 99's at least) there should be a little plaque-like thing with two dude's signatures and a 32 valve emblem thing if its a Cobra (DOHC)

Steve

97snakedriver · 02-01-2000, 04:04 AM

The Cobra engine looks a lot different then the GT. If there's a running hourse emblem then its a GT, if a snake and signature plaque (96 and up) then its a Cobra. If it has a single throttle then its a GT, if its has a dual then its a Cobra. There are more differences, but those are the easiest to explain. If you would like to see a picture let me know, I'll post the URL.

As far as the meat of your question: 4.10s. 4.11s were the ratio available on the old 7.5 inch rear ends used on GTs in the '80s and 6 bangers till now. 4.10s are the 8 inch ratio. Not that it makes much difference (ratio wise at least), but lots of guys (friends and relatives) who are used to the old set-up tend to say that. As is the nature of DOHCs, the Cobra engines likes the higher RPMs then a SOHC or push-rod engine. A stock Cobra would be quite happy to rev to 7500 if it were allowed. The SOHC is happier in the mid-range. Basically 3.73s let the GTs get into their powerband nicely without running out of breath. 4.10s (or 4.30s) let the Cobras get into their power band quicker. I would deffently recomend 3.73s for a GT. This assumes street tires.

------------------
'97 Cobra, K&N, Flowmaster, subframes, 4.10 gears, Steeda Tri-Ax shifter, Steeda G-Trac 3, Cobra R wheels w/ Goodyear F1s

[This message has been edited by 97snakedriver (edited 02-01-2000).]

RedTwilight · 02-01-2000, 08:39 AM

The Cobra motor should be noticeably wider. I read that it is 4inches wider than a 460 BB. Someone told me that the 4:10's would feel as if the car had 60 more hp over the 3:73's with out that much of a difference in gas milage(on a Cobra anyway). Like the other guys said 3:73's would probably be the way to go on a street driven GT w/5-speed.

------------------
'96 Cobra

97snakedriver · 02-01-2000, 11:05 AM

4.10s make the car feel like its 600 lbs lighter. Its nice. I have not had any noticable loss of gas milage in the city or on the highway.

93CobraR · 02-05-2000, 10:30 PM

Go for the 4.10's(don't think there is a 4.11) if it's a Cobra and the 3.73 if it's a GT. Good Luck!

------------------
87 Gt with 4 inch cowl hood, dark charcole grey, long tube headers,off road h-pipe, 2 chamber flows,BBK cold air intake, Mass air coversion(ported stock MAF), 1 intake spacer, Hypertech superchip, MAC underdrive pulleys,Pro 5.0 shifter, and a King Cobra clutch,Crane adjustable fuel press. regulator, Mac Strut and Tower Brace. 4.10's (new for this season)
Best time 14.91
Best MPH 103

Visit my site at:
http://www.geocities.com/cobrar93_20...l?947947194470

4cammer · 02-06-2000, 08:20 PM

T-Bone,

I agree with Hammer. The 3:73s are a very good compromise for both street and highway driving. The 4:10s are less noticeable in a Cobra, with its higher redline of 6800. I like mine. And yes, there is a BIG difference (not just on the outside) from the SOHC GT engine and the DOHC Cobra engine.

By the way, my cousin, Sean Bowen, is based at Minot (13 years now?). I'm always poking fun at him up in the cold, and now it was 21 frigging degrees here in Tallahassee, FL last night! Guess the laughs on me! Good luck with your gear decision.

------------------
'96 Cobra - K&N, Pro-M 77, Pro 5.0 shifter, 3:73s, Cobra "R"s, Steeda control arms, pulleys, springs and caster/camber plates.

01-31-2000, 06:03 PM	#1
T-Bone Registered Member Join Date: Jan 2000 Location: Minot AFB, ND Posts: 138	4.11 or 3.73's and sohc or dohc Hey Guys, Thanks for all of your help recently. I've got a couple more questions for you now. First, a friend of mine, who is a mechanic, told me I should go with 4.11's. I've noticed that most of the GT's have 3.73's and the Cobra's have 4.11's. How much will the two different gears change low end and high end performance? I want to make the right decision and get the gears that will suit me best. I guess I want to get up and go faster. I don't really care if the top speed is decreased that much. What will the top speed be with both gears, if anybody knows? Second, the mechanic also told me that he's pretty sure it's a DOHC, by looking at it. I'm not sure, but I fiqured it was SOHC since thats what most or all of the 96' GT's seem to be. I have no owners manual to refer to for the specs. How can I find this out for sure? Thanks in advance! T-Bone

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01-31-2000, 09:01 PM	#2
Hammer AKA "Dr. Evil" Join Date: Feb 1999 Location: South Fork Ranch Posts: 1,721	Well, any mod motored GT is SOHC stock, no matter how you cut it. Since I haven't stuck my nose under the hood of a Cobra very often, I couldn't tell you just what the cosmetic differences might be. (Athough I do think that the intake is noticeably different). So unless whoever owned the car before you put an awesome amount of money into this vehicle, I doubt it's DOHC. As far as gears, If you're staying light to moderately modded for now, run a 5-speed, and use this thing as a daily driver, 3.73s are for you. Plenty seat of the pants get up and go while retaining most of your top end and gas mileage. The ratio fits the power band of an SOHC mod motor to a T. There has been some debate about some automatic users going to 4.11s without major mods, but I have yet to see one in actual use to have a reliable comment for autos. In my opinion, you might just be cutting off a little too much streetability with 4.11s. One more thing, Be sure to get a shifter for those gears... You won't regret it! ------------------ 98 GT Dyno-Max cat-back exhaust, 3.73 gears, Steeda shifter, Ford Motorsport Underdrive pullies, 87mm MAF and Roush cold air kit...

01-31-2000, 09:17 PM	#3
T-Bone Registered Member Join Date: Jan 2000 Location: Minot AFB, ND Posts: 138	cool, thanks again Hammer!

02-01-2000, 01:45 AM	#4
Dynamite69 Registered Member Join Date: Feb 1999 Location: Orange County, California Posts: 12	Look at the intake, if there is a big Cobra on it, then its a DOHC.. also look at the passenger side valve cover (for 99's at least) there should be a little plaque-like thing with two dude's signatures and a 32 valve emblem thing if its a Cobra (DOHC) Steve

02-01-2000, 04:04 AM	#5
97snakedriver Registered Member Join Date: May 1999 Location: Blacksburg, VA Posts: 1,526	The Cobra engine looks a lot different then the GT. If there's a running hourse emblem then its a GT, if a snake and signature plaque (96 and up) then its a Cobra. If it has a single throttle then its a GT, if its has a dual then its a Cobra. There are more differences, but those are the easiest to explain. If you would like to see a picture let me know, I'll post the URL. As far as the meat of your question: 4.10s. 4.11s were the ratio available on the old 7.5 inch rear ends used on GTs in the '80s and 6 bangers till now. 4.10s are the 8 inch ratio. Not that it makes much difference (ratio wise at least), but lots of guys (friends and relatives) who are used to the old set-up tend to say that. As is the nature of DOHCs, the Cobra engines likes the higher RPMs then a SOHC or push-rod engine. A stock Cobra would be quite happy to rev to 7500 if it were allowed. The SOHC is happier in the mid-range. Basically 3.73s let the GTs get into their powerband nicely without running out of breath. 4.10s (or 4.30s) let the Cobras get into their power band quicker. I would deffently recomend 3.73s for a GT. This assumes street tires. ------------------ '97 Cobra, K&N, Flowmaster, subframes, 4.10 gears, Steeda Tri-Ax shifter, Steeda G-Trac 3, Cobra R wheels w/ Goodyear F1s [This message has been edited by 97snakedriver (edited 02-01-2000).]

02-01-2000, 08:39 AM	#6
RedTwilight Registered Member Join Date: Dec 1999 Location: Roxboro, N.C. Posts: 60	The Cobra motor should be noticeably wider. I read that it is 4inches wider than a 460 BB. Someone told me that the 4:10's would feel as if the car had 60 more hp over the 3:73's with out that much of a difference in gas milage(on a Cobra anyway). Like the other guys said 3:73's would probably be the way to go on a street driven GT w/5-speed. ------------------ '96 Cobra

02-01-2000, 11:05 AM	#7
97snakedriver Registered Member Join Date: May 1999 Location: Blacksburg, VA Posts: 1,526	4.10s make the car feel like its 600 lbs lighter. Its nice. I have not had any noticable loss of gas milage in the city or on the highway.

02-05-2000, 10:30 PM	#8
93CobraR Registered Member Join Date: Oct 1999 Location: Cincinnati, Ohio Posts: 1,575	Go for the 4.10's(don't think there is a 4.11) if it's a Cobra and the 3.73 if it's a GT. Good Luck! ------------------ 87 Gt with 4 inch cowl hood, dark charcole grey, long tube headers,off road h-pipe, 2 chamber flows,BBK cold air intake, Mass air coversion(ported stock MAF), 1 intake spacer, Hypertech superchip, MAC underdrive pulleys,Pro 5.0 shifter, and a King Cobra clutch,Crane adjustable fuel press. regulator, Mac Strut and Tower Brace. 4.10's (new for this season) Best time 14.91 Best MPH 103 Visit my site at: http://www.geocities.com/cobrar93_20...l?947947194470

02-06-2000, 08:20 PM	#9
4cammer Registered Member Join Date: Aug 1999 Location: Florida Posts: 99	T-Bone, I agree with Hammer. The 3:73s are a very good compromise for both street and highway driving. The 4:10s are less noticeable in a Cobra, with its higher redline of 6800. I like mine. And yes, there is a BIG difference (not just on the outside) from the SOHC GT engine and the DOHC Cobra engine. By the way, my cousin, Sean Bowen, is based at Minot (13 years now?). I'm always poking fun at him up in the cold, and now it was 21 frigging degrees here in Tallahassee, FL last night! Guess the laughs on me! Good luck with your gear decision. ------------------ '96 Cobra - K&N, Pro-M 77, Pro 5.0 shifter, 3:73s, Cobra "R"s, Steeda control arms, pulleys, springs and caster/camber plates.