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?
 
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
 
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: