8.75 Ratio opinions

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G

GBM

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I have a 71 swinger with a 408 about 450 hp and 500 ft lb torque with a 727 auto and a open 3.55 rear end ratio " one wheel peeler " lol and am going to put a sure grip in it from dr diff but unsure if I want to keep the 3.55 or go to a 3.73 ratio . car is used for car shows and fun . comments greatly appreciated . thanks
 
what is your rear tire size and coverter stall rpm? this makes a difference if you want to go on highway for any distance.
 
ok with the3.55@60 mph rpm is 2773
with 3.73 @60mph rpm is 2914.
141 rpm difference
if most of your driving is city
stop sign to stop sign id go 3.73
if your on higheay alot 3.55 is a good choice. hope this helps
alot of members like the 3.55:steering:
 
4.30 baby. Go big or go home. lol

All kidding aside, your combo would set on fire with that gear. IF you did that, I would recommend going to a 27" tall tire.
 
Stick with the 3.55s - put a posi. unit in it, and use the gears that You have -- save a few $, and enjoy.
 
Your gear choice is somewhat limited by the housing you have 741 very limited new gear ratios, 742 more ratios, 489 a few more. either way 3.55 and 3.73 is available in all 3 IIRC

I agree 3.55 would be a good compromise HWY / Street.
 
with 500 ft lbs of torque, I'd run 2.94 sure grip in a street car. JMO
 
I'm with 318willrun in that a taller gear might even be just fine. I have a 68 Cuda FB and it's a heavy pig (3450 empty) and a 408 making about the same power you say yours is and right now I'm running 3:55's with much taller tires than you at 275/60/15 but I'm planning on swapping back to 3:23's that I had in it previously. The 3:55's are great for racing and ok for the street but with 500 lbs ft of torque on hand and a 3K stall or higher there isn't much difference in how quick it is with 3:23's and it runs 250 less rpm down the hwy. If you drive a lot taller gears are your friend too. The 3:23's I had in mine got nearly 2 mpg better than the 3:55's... JMHO
 
I want to thank you for your comments here, as what you have, is what I am planning for my little beast. Needs an engine rebuild, so why not just go the 408, with low compression. My 360 is suppose to be 10.5 and I think that a 9.5 would be much more comfortable, and still have the torque that I want. And, I was unsure of the gear: 3:55 or 3.23. Granted, in high performance old Mopar, gas mileage isn’t brought up much, but let’s face it, it’s nice to have somewhat decent gas mileage. 3000 at 60 mph doesn’t cut it for that. Again, thank you for helping me decide.
 
As 318 willrun says 2.94 or 3.23. I'd think you'll have nothing but tire spin with 3.73 in 3 gears.
With 3.73's and 500ft.lbs. in an A body it might be tough to beat anything at a street light.
 
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