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67 swapping out the 4.88s

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67 street 427 4 speed 27 inch tire best rear gears?

  • 4.11

    Votes: 5 14%

  • 3.73

    Votes: 25 69%

  • 3.90

    Votes: 5 14%

  • keep the eggbeater 4.88s

    Votes: 1 2.8%
  • Total voters
    36
  • Poll closed .
1 - 20 of 21 Posts
#2 ·
What do you use the car for,
- just street cruzin
- street and Hwy cruzin
- street/hwy/strip

I have 3.55s in my 12 Bolt with a 3 speed Auto so final ratio in = 1.00 just like your 4 speed manual

I use 28" tall tires for the street/hwy and 26" tires for the strip .

One day hope to put a 4 speed auto into the car so therefore would then like/need 3.73 rear gears as the final trans ratio would = .67/.70 .
 
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Discussion starter · #4 ·
74malibu said:
I went from 4.88 to 3.90 last year. I lost some 60' (1.48 to 1.53ish) but it was worth the trade off for street driving. With your M20 I wouldn't hesitate to go 3.90 or even 3.73. Your car will still feel plenty strong.
Click to expand...
Im not to worried bout losing some acceleration ......

but don't wanna kill it in the same token.....

I think if you talk 1/4 mile times, I think it might be faster with 3.90s,but just my opinion.
thanks for reply
 
Discussion starter · #5 ·
74malibu said:
I went from 4.88 to 3.90 last year. I lost some 60' (1.48 to 1.53ish) but it was worth the trade off for street driving. With your M20 I wouldn't hesitate to go 3.90 or even 3.73. Your car will still feel plenty strong.
Click to expand...
if I may ask,what is the weight on your Malibu?????? was looking at your e.t.
 
#6 ·
I voted 3.73, much nicer street cruising . My car pulls good with a 3.31 and 28'' tires ,but I have a small cam that makes low end torque and a 4'' stroke. I do wonder what a little more gear would do though :D.
 
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#7 ·
I've got a big block with 3.73's and F70-14 tires. I voted 4.11. Sometimes I wish I had 4.11's but I guess the 3.73 are a good compromise. If I had less than 450-500hp I would go 4.11.
 
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#11 ·
I just dropped form 3.98's to 3.70's and the car went faster......3535 lbs auto...
 
#15 ·
67RAT said:
Im dumping these unbearable 4.88 gears,what should I run?
Im thinking 3.90s !!!!

67 chevelle,street car.m20, 12 bolt, 550 or so hp 427,27 inch rear tire,rpm range 3000-7000

thanks bobh
Click to expand...
===========

If your doing the gear swap to reduce cruise rpm on street 3.73's for sure!

With your pretty stout 427/550hp thats plenty of umph to pull 3.73 just fine keeping in mind thers always a trade off in situations like this with non overdirve man trans when it comes to strip perf vs dirveability and not turning 3,500-3,600+ rpm at 60mph with 4.88's,(YIKES!!/could not stand it!/LOL!!!)

Heck,as suggested you could go with 3.55's and still have nice performing car with your hot 427 along with with even better/slightly lower cruise rpm.

I have 3.31's in my 69 with m20 ,26" tall tires,and mild built 396/now 402 bbc(approx 375-380hp/440-450;lbs trq) ,it runs pretty strong for what it is, turns approx 2,650rpm @ 60mph & 3k rpm @ 70mph with the 3.31's in it's 12 bolt.

3.73's in my car with m20 & 26" tires would turn approx 3k rpm @ 60mph.

Let us know what gear you go with and then how you like the result in rpm reduction at cruise and perf when pulling gears post installing them.

Good luck.

Scott
 
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#16 ·
YankeeRodder said:
3.73 on my street car. Nice around town, bad on highway. I need a 700r4
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=========== non od trans and

LOL!!!

You think 3.73's are rough rpm wise cruising on open road,man the 4.88's with m20 he's currently running must be brutal on the street with his non OD man trans esp if he's running stockish 26" tall tires.

The 4.88's have to be at least 3,600-3,700+ rpm @ 60mph unless he running taller then stock 28-30" tires!(YAK!!!!/LOL!!)

Scott
 
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#18 ·
Either way Bob 3.90 or 3.73. I'm using 3.31 and they're a bit weak with a 427 and a clutch imho, but I do long highway jaunts.
 
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Discussion starter · #19 ·
SWHEATON said:
=========== non od trans and

LOL!!!

You think 3.73's are rough rpm wise cruising on open road,man the 4.88's with m20 he's currently running must be brutal on the street with his non OD man trans esp if he's running stockish 26" tall tires.

The 4.88's have to be at least 3,600-3,700+ rpm @ 60mph unless he running taller then stock 28-30" tires!(YAK!!!!/LOL!!)

Scott
Click to expand...
ooooohhhh yea,60 mph almost gives 4000 rpm,tires are m/t indy profile L-60s bout 27- 28 tall,,,,

USED TO BE FUN IN THE CRUISE TOWN DAYS,NOW I WANNA TAKE THE CAR PLACES FARTHER OUT OF TOWN!!!!!!
yea the 4.88s gotta go,my chevy IIs been gobblin up my time and money,that got 4.10s with solid cam 427,4 speed,didnt drive yet so have no clue how that will act....
my chevelle is suffering and she needs new gears for sure....
 
Discussion starter · #20 ·
mr 4 speed said:
have no fear,big blocks don't need tractor gear :D
3.73 is a good compromise.
Click to expand...
I hear ya there,I actually think the car may run better with a 3.90-3.73 or so

with the 4.88s its bam,bam,bam,bam fouth gear and shes done!!!!!!!

almost seems the 88s hurt the cars acceleration....maybe im wrong,maybe its just me,,,
 
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67RAT
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