5sp 3.55 vs 3.73

Mach428

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Dec 7, 2003
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My brother owns a 88gt 5sp manual. Our next mod will be gears. My friend owns a 99 GT 5sp man and he put 3.73 into his car and I love the ratios. My question is, since the 99+ have 3.27 stock and the 5.0 have 2.73's, will 3.55 in an 88 gt have the same effect as 3.73 in a 99 gt?
 
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Well if you ask people with 3.55's alot of them wished they had gotten 3.73's. The difference in cruising RPM's in 5th is only a few hundred, not even. You gotta remember that the newer "fox" Mustangs(99+) are 2-300lbs heavier than an 87-93 5.0. The 4.6 isn't a gift of tq till around 4k RPM's. So they'll generally like more gear. I'm not too familiar with the 4.6's but alot of 4.6 guys like the 4.10's even w/ a 5 speed. I'm not sure about your question since there are many other factors to accoutn for between the 2 cars(hp,tq,drivetrain,weight,etc.)
 
3.73's for sure, I have them in my car, my friend has 3.55's in his car, it's not much of a difference, but when you get on it, you can tell and I can take him right off the line with my gears. I can cruise at 70mph at 2500rpms on the highway it's around 2300-2400rpms at 65mph
 
I put 3.55's in my 94 and thought they were the ****, then I put a set of 3.73's in my 95 and wouldn't have done it any other way. accept maybe 4.10's :) go 3.73's you won't ever regret it
 
it all depends on the future plans that you may have with the car. Some of my friends get 3.73's or 4.10, then later they add a supercharger and the gears are too much for traction. So they step down to 3.55's or 3.27's.

but if you have an N/A car go with the 3.73's

Good luck :nice:
 
Im NA . True superchargers could handle the higher gear. But i dont like the boost. So wont have to worry about it. Roots blowers seem to love the higer gears. 3.27 and 3.55s. I have a few friends with roots blowera and there cars work better with 3.27 gears. But as far as an Auto NA car goes. 3.73-4.10s
 
If you get 3.73s for a 5 speed, first gear goes by pretty quick. Get 4.10s and you can almost skip 1st altogether...I have a C4 so i cant compare all that much, but i'm running around 3 grand at 60mph with 4.10s, i'd imagine with a 5 speed it would drop a few hundred with 2 extra gears. I always wanted to have a tranny built with a real low 5th for cruizing and have the first 4 gears for racing.
 
BlackFox5.0 said:
3.73's for sure, I have them in my car, my friend has 3.55's in his car, it's not much of a difference, but when you get on it, you can tell and I can take him right off the line with my gears. I can cruise at 70mph at 2500rpms on the highway it's around 2300-2400rpms at 65mph

:stupid: Just made a 1500 mile trip in mine to Texas.... BlackFox is right on with the rpm's/mph, although I really think I was doing more than 70 when I was turning 2500 rpm's. I got the speedo gear replaced when I had the rear done, though... :shrug: I sure was passin' a lot of people, but never got pulled over by the Highway Patrol. :nice:

Anyhoo, for a daily driver that sees occasional highway use, I'd recommend the 3.73's. They are a blast!
 
i have had both 3.73's and 3.55's in my Mustang. There's not much difference except the cruising speed (for 4th and 5th) for 3.73's is at 2300-2500 rpm's and the 3.55's is at 2000-2200 rpms. I love the 3.55's but the 3.73's were not bad either. i don't think you could wrong with either selection.
 
Mach428 said:
Thanks for the tips, I guess we'll go with 3.73 cause we have n/a power, thanks for the advice

even with a power adder they are fine.. I ran 461 RWHP with my 3.73's, P1sc, and a few suspension upgrades and it was a total blast. Might be a bit much for a Kenne Belle blower but with any centifugal blower I wouldn't bat an eye at running 3.73's.
 
im also another person with 3:55's who wants them over 3:73's.

i drive on the freeway to go anywhere pretty much, i dont think i could take 2500+ rpms of flowmasters for an hour. right at about 2100 rpm's is where they really start speaking on the freeway, according to my 5" tach im doing 1800-2000 rpms at 70-75 :shrug: