373 vs 355 Pros? Cons?

SVT4MT

Well-known member
"Don't fear the gear" is quoted often. lol

I put FRPP 4.10's in my '06, one of the best mods I ever did, only regret was not doing it sooner.

Highway cruising wasn't adversely effected, and it was a monster off the line, first gear was a little shallow, but man it pulled.

I can't recall what it cost, but it was worth every cent.

3.73's would be a great mod, but don't be scared of 4.10's.
 

S197CS

Corner Carver
Glenn,

To be clear, it does not get ''rid'' of the drone, it simply moves when you're encountering it. Ex.: at 105/110 km/h right now, she's right around 2000rpm (give or take), so right in the ''drone zone'' (1800-2000RPM). That's on 3.55 in 5ft. On the 3.73, at the same speed, I should see the RPM around 2300-2400rpm, JUST out of the drone zone. Shorter gear, so at the same speed it'll be higher in the rpm range.

I didn't go higher (4.10) as I feel the 3.73 will provide me the balance I am looking for for getting out of the drone RPM band on the cruising around, not affecting ''too much'' the MPG and still be a blast around the autocross track. 4.10 for me would render my car useless.

Planning to install somewheres in may/june next year, keep an eye on my build tread for an update, if you didn't do the jump yourself by then. ;)
 

IRONMAN

Well-known member
"Don't fear the gear" is quoted often. lol

I put FRPP 4.10's in my '06, one of the best mods I ever did, only regret was not doing it sooner.

Highway cruising wasn't adversely effected, and it was a monster off the line, first gear was a little shallow, but man it pulled.

I can't recall what it cost, but it was worth every cent.

3.73's would be a great mod, but don't be scared of 4.10's.
I’ve been thinking on the Ford Racing 4.10, but I was not sure about how will affect cruising.
 

2001BlackGTvert

Moderator
Staff member
I went 4:10 in My 01 Auto as mentioned above. The get up and go was night and day and I would do it again in a heartbeat. I actually regret not doing it right away.lol I went back and forth from 3:73 to 4:10 for a long time and did lots of reading and I am glad i chose the 4:10. It obviously reves higher on the highway, however not unreasonable.

There are plenty that are more then happy with the 3:73. Its just a matter of preference.
 

Ohtobbad

Administrator
Staff member
I went 4:10 in My 01 Auto as mentioned above. The get up and go was night and day and I would do it again in a heartbeat. I actually regret not doing it right away.lol I went back and forth from 3:73 to 4:10 for a long time and did lots of reading and I am glad i chose the 4:10. It obviously reves higher on the highway, however not unreasonable.

There are plenty that are more then happy with the 3:73. Its just a matter of preference.
I agree, auto / manual can make a difference.
HP as well, more you got 373's make sense.
less you have 4,10's make more sense.
also your driving preference,
out of the hole fast and furious or
little extra torque with long drives.

As always each person wants something different.
 

Mineral Grey

Well-known member
Here is the link to where I discuss how to predict your new rpms with changing gears . This might help with your decisions ..
 

IRONMAN

Well-known member
Here is the link to where I discuss how to predict your new rpms with changing gears . This might help with your decisions ..
Very interesting. 😎
 

S197CS

Corner Carver
Mine came with 3.55 stock, then jumping to 4.10 seems right. Will think during the winter about it.
Anyone on a manual and 4.10?
For the records, mine came with the 3.55 as well, being a manual 105-110 is right at 2000 or extremely close, so the 3.73 will work for the drone purpose and, the 4.10 would be a lot too short for the autocrossing that I do every once in a while every summer (Except this one I guess, stars didn'T align for me to join the fun). 3.73 will be perfect compromise on all fronts for me. Will report next year in my build tread.
 

67 AGAIN

Enthusiast
$1500.00 is a rip off for gear swap.
It should be around $500.00.

Drone is mot a product of gears.
It is a product of engine harmonics and it occurs right at 2000 rpm +/- 100 rpm.
Max will not get rid of drone, he will only move where it occurs.
He likes to cruise at 105-110 km/h but now that is giving him drone because he is at 2000 rpm at that speed.
By changing gears, his drone will now occur more at 90 km/h because he will hit 2000 rpm sooner.
By the time he gets to his preferred cruising speed of 105-110 he will be over 2000 rpm and the drone will be done.
He will cruise happily. 😁

3.55 to 3.73 is a very small jump but a jump nonetheless.
It won’t adversely affect your mileage much.
With the supercharger, it should be a nice combo.
With, S/C, 4.10’s not necessary.
Unless you race or have specific nedd, probably too much and you would have buyers remorse.
So, yes, S/C does make some difference.

In general, more aggressive gear swaps are more popular with N/A cars.
Relatively inexpensive, hot rodder way of making car more responsive.

Both the 4.6 modular and Coyote are relatively low rpm torque engines.
They ate engines that make power and torque at higher rpm’s.
I’m talking 3500 to 4000 and up.
With synthetic oils and good maintenance/filters, wether you cruise at 21-2200 or 25-2600, it does not matter much.
That is steady state driving and there is plenty of oil to lube everything.
You can do way worse to your car.

For S-197 cars, the auto transmission cars have shorter 1st and 6th gears than manual cars so 3.55 and 3.73 are good upgrades.

For manual cars, 3.73 and 4.10 are good upgrades.
Don’t fear the gear is right.

But it all boils down to your preferences and what you seek from your car.
If you are conservative, go with the lower of the two.
If more hard core, go with the higher of the two.

From personal experience, a one size augmentation is very friendly and little affect on drivability and fuel efficiency.

Each generation is different, so you should know what your car was born with before you do anything.
A 3.73 in an SN-95 won’t have same affect as on S-197.

S-197 autos are born with 3.31, so 3.55 is one size larger and 3.73 is two sizes larger.
S-197 manuals are born with 3.55, so 3.73 is one size larger and 4.10 is actually three sizes larger
That’s because Ford no longer makes a 3.90 gear set.
But 3.90’s are available from other manufacturers.
3.90 would be the two size larger jump.
But the overdrive in the manual transmissions of the S-197 cars is so tall that they can run the 4.10 with little or no significant negative impact.

That’s why 4.10’s are popular on 05 to 14 manual N/A cars.

I’ve done 3.31 to 3.55 on 05 automatic.
Liked it and still very drivable and near stock.
I’ve done 3.55 to 3.73 on 06 manual
Same result as above.
But the wow factor really came when I did 3.90’s in 06 manual, especially with ported heads and bigger cams where I had lost low end torque.
So now’ I Know I want 4.10’s and have a set on the shelf and they are going in next summer.

More recently I did 3.15 to 3.55 swap, two size jump, in 15 automatic car and noticed good difference in pull but very little affect on drivability.
In fact, on the fall run, I was getting pretty much same mileage as my cousin in his 19 Bullitt with manaul and 3.73 gears.
And he was not getting away.

General rule is that at highway speed, so 110 to 120, rpm goes up about 250 to 300 rpm per gear size increase.

Max, you mention you may hit 2400 at same speed.
I think that’s a bit much.
You’ll probably be more around 2250-2300.
Still safely out of drone zone.

Glen, 3.55 to 3.73 in your car is a very safe swap.
Only you can and should decide.
But it will not eliminate drone.
It will ochange the speed at which it occurs.
It will occur at a slightly lower speed than it does now. Always around the 2000 rpm mark.

If drone is your main reason for considering gears, than you are not doing it for the right reason.
To eliminate drone, you need to change you mufflers or axle back exhaust.

For that, Borla and anything they make, such as Ford Performance and I believe Roush, are the best.
Again from personal experience, I can attest.
Ford Performance on the 15 = zero drone.
Magnaflow on the 06 = some drone.

Happy and good decision making.
 
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