What do you guys think about 3.55's?

The Green GT

No 13 year olds are safe around me.
10 Year Member
Jan 8, 2006
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I was planning on putting 3.73's in my '94, but after talking with D.Hearne who is a Site founder and a father of my best friend he thinks I should put 3.55's in it. This is his explanation.
D.Hearne said:
If you're going to do a gear swap, I'd go with 3.55's instead. 3.73's are a little much. You'll float the valves everytime you nail it in 1st, cause it'll tach out before you're ready to shift. 3.55's with your rear tire diameter is equal to what I've got in the Ranger with it's 3.73's, 28" tires and the Toploader's 2.78 1st gear.
 
def. 373's
I had 355's in a mild H/c/i 5.0 w/ bald tires and it wasnt enough gear. also sucked b/c at 50mph in 5th gear teh rpms were too low and it would bog down (e303)
I had 4.30s in my last car and it was fine
 
I HAVE 3:55'S ...they were in it when i bought it.... i like them, they're nice, if you're looking for highest top speed running from the cops on the interstate go with them... haha.
Go with 3:73's, i want to swap to them. ...i have a 5spd btw.. n' 5th at 50 bogging is why you leave it in 4th haha, until it's time to shift... no but reallly 55 in 5th is like 15-1600 rpm if you're wondering and not really bogging
 
Originally Posted by D.Hearne
If you're going to do a gear swap, I'd go with 3.55's instead. 3.73's are a little much. You'll float the valves everytime you nail it in 1st, cause it'll tach out before you're ready to shift. 3.55's with your rear tire diameter is equal to what I've got in the Ranger with it's 3.73's, 28" tires and the Toploader's 2.78 1st gear.

1) Toploader :shock: Old School 4 speed trans

2) 28" tall tires :shrug: doubt if your tires are that tall

Not too sure if 1 & 2 can be used to help you get an idea about your gear ratio choice.

You never said if you're a stick or an auto :shrug:
but
I'd go no less than 373's :) IF you're gonna stay NA

Here ... Play with this and let the math give you facts as opposed to all of our opinions :D

http://www.allfordmustangs.com/Detailed/608.shtml

Grady
 
I have a 5-speed.

Question about 3.73's VS 3.55's: How do they affect your shifting. Like right now I have to shift to second at 40 and to 3rd at 75-80. How do 3.73's change that and how do 3.55's change that? Also, how does it affect gas miledge. This is my daily after all.
 
The Green GT said:
I have a 5-speed.

Question about 3.73's VS 3.55's: How do they affect your shifting. Like right now I have to shift to second at 40 and to 3rd at 75-80. How do 3.73's change that and how do 3.55's change that? Also, how does it affect gas miledge. This is my daily after all.

Going by your sig...which looks like your basically stock??? 373s would be a wiser choice for more hit/fun....I was mooded and ran 355s for 2 seasons...They're nice and a much needed improvment over the stock 273s...I then went to 373s and like them better...1st is kinda short, but from there on out they're the balls...5th will actually be usable with em...
You speedo will be off with the 373s and your milage should take a small hit...But Mustangs ain't for MPG anyway..:D
 
i have a c4 3 speed automatic and 3;50's are about the maximum that i can go for it to be streetable on the highway. if i went to 3;70's i would be taching out at like 4 grand going 65-70mph! and I would be topping out at like 110 mph. old school c4 3 speed slushboxes, gotta love em'
 
That’s a great calculator, but I am confused. If that is accurate, I got these numbers:
T5 with 245x45x16 tires (stock)

3:55's (I have these) at 70mph
3rd 4501
4th 3384
5th 2301

This is consistent with my car.
Now are these numbers consistent with anybody's car with these gears?

3:73's 4:10's at 70mph
3rd 4729 5198
4th 3555 3908
5th 2418 2651

The reason I ask is most people are against 4:10's on the highway, because the car will be "screaming" the whole time. "If you do a lot of driving on the highway, don't get 4:10's". I don't think 2,651 rpms is screaming at all. I drive 90 miles, round trip, to work each day and I believed the highway gear horror stories and settled for 3:55's. If these numbers are accurate I'm getting some 4:10's. Can anybody confirm these numbers?
 
RIO5.0 said:
Going by your sig...which looks like your basically stock??? 373s would be a wiser choice for more hit/fun....I was mooded and ran 355s for 2 seasons...They're nice and a much needed improvment over the stock 273s...I then went to 373s and like them better...1st is kinda short, but from there on out they're the balls...5th will actually be usable with em...
You speedo will be off with the 373s and your milage should take a small hit...But Mustangs ain't for MPG anyway..:D
Its stock except for the roller rockers, there the ones from a Cobra I think, and king Cobra clutch kit, and straight pipes with side exhaust. And just how much will my speedo be off?
 
I've got 4.10's in my Cobra (they were in the car when i bought it) and kind of wish I had 3.73's, simply because i spin through first no matter what and through second if i nail it (keep in mind this is just with bolt-ons). It'll go about 30 in 1st, 50 in 2nd, 75-80 in 3rd, and 100 in 4th.

R.J.- Those numbers are right on for 4.10's at 70, and at 50 I'm turning around 1900.

That being said, if I ever get any big mods, I will pretty much have to get a lower gear if I ever want to use first. But for a bolt-on car, assuming it's not driven exclusively on the highway, 4.10's are great, especially for impressing your friends with crazy fast runs up to 100. Hope that helps.
 
The Green GT said:
Its stock except for the roller rockers, there the ones from a Cobra I think, and king Cobra clutch kit, and straight pipes with side exhaust. And just how much will my speedo be off?

I can't recall the exact number but you'll notice it right off...You go for a ride after the swap and it'll be cruising at like 90 or some crazy chit....:D
I put in a White 21 tooth gear in and mines still off buy 4 MPH or so, thats according to those radar things the cops put out...
If you have high miles you should also do the Trac-Loc rebuild....with gears you'll tend to wanna smolder the tires more often cause its easier...:nice: