Automatics with gears?

scupking

Active Member
Sep 18, 2005
1,186
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36
Enfield, CT
I need some opinions. I was going to get a super charger next year but need to spend some money on getting my rear end rebuilt. I also will be getting H&R sport springs, Blistens new rims and tires. That leaves me with not much money. So I was thinking of just getting gears and not get a super charger for at least 2 years or so. My problem is I keep thinking 4.10s will be to much gear. I drive at 80 on the highway as do most people around hear. With OD on I'm at about 2,400 RPM with OD off I'm at 3,000 RPM. I just don't no what to go with, 3.73s or 4.10s? I need some opinions from some automatic people.
 
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I need some opinions. I was going to get a super charger next year but need to spend some money on getting my rear end rebuilt. I also will be getting H&R sport springs, Blistens new rims and tires. That leaves me with not much money. So I was thinking of just getting gears and not get a super charger for at least 2 years or so. My problem is I keep thinking 4.10s will be to much gear. I drive at 80 on the highway as do most people around hear. With OD on I'm at about 2,400 RPM with OD off I'm at 3,000 RPM. I just don't no what to go with, 3.73s or 4.10s? I need some opinions from some automatic people.

Go 4.10's, I had 3.73's in my GT, wasn't impressed
 
I need some opinions. I was going to get a super charger next year but need to spend some money on getting my rear end rebuilt. I also will be getting H&R sport springs, Blistens new rims and tires. That leaves me with not much money. So I was thinking of just getting gears and not get a super charger for at least 2 years or so. My problem is I keep thinking 4.10s will be to much gear. I drive at 80 on the highway as do most people around hear. With OD on I'm at about 2,400 RPM with OD off I'm at 3,000 RPM. I just don't no what to go with, 3.73s or 4.10s? I need some opinions from some automatic people.

Ive had 4:10's in all 3 of my mustangs (all auto's) and would recommend them. Trust me, you will not be happy with a N/A auto car with 3:73's...not much diff than 3:27's, though better. If and when you get boosted, then maybe switch to the 3:73's. On a side note, if you plan on getting LT headers, the H&R ss's might be a bit too low for you (though they make some of the best springs out there), just a thought. GET the 4:10's.
 
I've traveled from CA to CO with my 4.10 geared 2kGT At cruise you can't really tell much... and I have LM1s. but I love that muscle car rumble. I turn about 2800 at 75 also. But I'm at 2k at 55mph...

hey youre in sonora correct (Im on ca-mustangs), where did you get yours installed? i need to take my GT and get the rear end rebuilt, the moan on takeoffs are coming back after they went away for about a month since i replaced the rear rotors, so im gonna get the entire rear rebuilt with gears, the install+rebuild kit, and new axle bearings.
 
When I had FRPP 4.10's I drove street and highway driving
and the 4.10's just ruined my MPG.I wished I had gotten 3.73's
instead.Since you care about your MPG like I did you should just
get FRPP 3.73's and be happy with them.
Good luck with your rear end rebuild though.
 
I drive about 30 miles round tripe from work a day on the highway going 80. I do lots of tripes down to the coast which is a little over an hour drive at 80mph. So then 3.73s sounds like the better option for me. I'm thinking 3.73s will put me around 2,800 RPM at 80. The good thing is then that will push me to get a super charger down the road:D
 
I drive about 30 miles round tripe from work a day on the highway going 80. I do lots of tripes down to the coast which is a little over an hour drive at 80mph. So then 3.73s sounds like the better option for me. I'm thinking 3.73s will put me around 2,800 RPM at 80. The good thing is then that will push me to get a super charger down the road:D

If your SC is two years out, get the 4.10's. It won't cost you that much now, nor to replace them when the SC goes in. Say you pay $400.00 or so to have them installed (with the parts). If you average that $400.00 over two years, it isn't that much. Just change them again when you get boosted.

For the time you're NA, you'll enjoy the 4.10's. 3.73's on an NA auto are a waste.

Also, if you're concerned about gas mileage, you shouldn't have bought a GT. If your timing isn't advanced, you can run 87 fine and your gas bill shouldn't be that much.
 
1. Who runs 87?
2.Why buy gears twice? Especially when he's going to be spending a lot on a supercharger/install/tune.
3. 3.73's is not a waste.
4. Who here isnt concerned about gas milage? Yeah we bought GT's not worrying about it obviously, but who bought thier mustang while gas was 3.40/gal?
 
If your SC is two years out, get the 4.10's. It won't cost you that much now, nor to replace them when the SC goes in. Say you pay $400.00 or so to have them installed (with the parts). If you average that $400.00 over two years, it isn't that much. Just change them again when you get boosted.

For the time you're NA, you'll enjoy the 4.10's. 3.73's on an NA auto are a waste.

Also, if you're concerned about gas mileage, you shouldn't have bought a GT. If your timing isn't advanced, you can run 87 fine and your gas bill shouldn't be that much.

I never said I cared about gas mileage. I have a 93 oct. tune from Tim at MPH. I just don't want my RPMs to be crazy on the highway. I will be getting a transmission cooler also.
 
I have 3.73's and an auto, and my speedometer is messed up and I still have no idea how fast I really am going, but I tach about 2500 when really crusing on the highway and I'm just going with the flow of traffic and/or passing the slower cars, so I would say that's about how it will be. What is the optimum RPM in O/D for the 4r70w for the best MPG on the highway? At 2500 rpms my exhaust is really, really loud, and it seems like this would equate to bad gas mileage?
 
I have 3.73's and an auto, and my speedometer is messed up and I still have no idea how fast I really am going, but I tach about 2500 when really crusing on the highway and I'm just going with the flow of traffic and/or passing the slower cars, so I would say that's about how it will be. What is the optimum RPM in O/D for the 4r70w for the best MPG on the highway? At 2500 rpms my exhaust is really, really loud, and it seems like this would equate to bad gas mileage?

I have an Xcal 2 so I can fix my speedometer without a problem when I get gears. Just trying to figure out if 4.10s would be to much.
 
1. Who runs 87?
2.Why buy gears twice? Especially when he's going to be spending a lot on a supercharger/install/tune.
3. 3.73's is not a waste.
4. Who here isnt concerned about gas milage? Yeah we bought GT's not worrying about it obviously, but who bought thier mustang while gas was 3.40/gal?

1. Anyone who's timing is stock or doesn't ping on 87. If that's you, and your run higher than 87, you're flushing your money down the toilet.
2. Some do
3. For N/A it is.
4. Me. I get free gas :nice: