3.31 to 3.73 worth it?

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trebor75

trebor75

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Hello all! Will it be worth the work changing from 3.31 to 3.73 ratio? I have the 741 center and the 3.73 is the "biggest" gear I can find for that center. I want to be quicker of the line. Also played with the thought of changing to a higher stall converter.

My current combo:
1965-273
727
340 Cam
Edelbrock D4B intake / Edelbrock 600 Performer Carb
Headers
2.5" Dual Exhaust
8 3/4 - 3.31 - SureGrip
 
Yes it,ll help you off the line more.Do you drive on the highway?3.73,s won,t be all that much difference.Have you thought about a second set of rear tires for the track?Smaller ones will make a difference,just like a taller one will.You could always get a second center section also with a different gear for the track.Just sayin..:burnout:
 
Well worth it I went from 323 ratio to 3.91 gears and it was a big difference especially off the line
 
Thanks guys!

I went from 2.76 to 3.31 and it did make a lot of difference. Now I'm starting to think I should have put the 3.73's on there immediately :) I'm not that motivated going through all that work again I guess, thats why I ask.

I do some highway driving from time to time and I forgot to write I have the 245/60 14 tires on the back.

I might have a chance on getting a whole center with 4.10 ratio. is that to much if you want to go for a longer ride from time to time?
 
4:10's are definitely not highway friendly. My Cuda had them in it when I got it and I hated them. At 60 mph. it sounded like the engine was going to blow. Tell me something, why do you have a 727 behind a 273? That's a power sucker right there. There's absolutely no need for a 727 behind such a small engine built that mildly. Switch to a 904 with the low gear set (most refer to it as the 999) and you'll gain just as much as swapping to 3:73 gears and it'll drive down the hwy. just like it does now and get better gas mileage doing it. Put a 2500 stall in it and it'll be even faster.
 
Thanks Fishy. My Duster was a slant 6 car when I bought it and it's also my first project car ever. I got a really good deal on the 273 and 727 that came out of a friends Dart. I never knew or considered that 727 being a power soak behind the little 273. I was happy getting a good working 727 for a bargain, and when budget alows I could put a bigger engine in the Duster. The thing is, in Sweden where I live, it's hard to find parts and they are 3 times more expensive then in America. That being said I will now keep an eye on the ads for a 904.
 
If you have the 3:73's already, by all means put them in there. I think you'll be happy with them!!! Geof
 
3.73 is a good ratio for your application,3.91 would be a bit too much. The swap is well worth it, you will notice a difference...Years ago i owned a 70 dart 340 w/4 speed and a3.23 open rear,,, What a dog!! Installed a new center section w/ 3.91 and sure-grip,, it felt like it had a 440 in it.....
 
I remember a buddy of mine switched from a 3.23 one wheel peel to a 3.55 sure-grip and you could notice a difference. Livened the car right up.
 
Do it. Great modification for instant "seat of the pants" gratitude.
 
Well worth it , better off the line , still drive-able on the highway .
 
You all convinced me :) I'm doing the swap and going with 3.73's! Already looking forward to it.

All the bearings and the sure grip is in good condition, so what do I need besides the ring and pinion? Can I ree-use everything (besides gaskets) or do I need a different bearing for the new pinion?
 
3.55-3.73 is right around the gearing area where you will begin noticing the tradeoffs making a big difference, depending on tire size. I have 3.73s and 255/60 15s on my Duster and it is tolerable on the highway, but not a long distance cruiser by any means. Going from 3.23 to 3.73 made a big improvement off the line, to the point where it started becoming traction-limited depending on the road/track surface. It needs 3.91s to be a really good combo with that tire size.
 
Ugh, wished I didn't see this thread. I went from 3.23 to 3.91 ten years ago and love how well each gear is driving around the 50--55 mph zones. Can run around town 1/3 throttle shifting 1st to 2nd @ 30 mph, 2nd to 3rd @ 45 mph. Works perfect around town but yeah for long distances--over 30 mins 75 mph 4,000 burns up the fuel fast. So thinking of sticking those 3.23's back in and going on road trips a few hours each way.....ugh, no more lightening fast take off's though
 
I went out to diner tonight and drove on the E way, 40% of traffic late summer now in michigan is going 75 mph in the 70 zones--that is flying for us winter folks who know you can get killed in the winter driving those speeds, lol

So I checked it out, with 27 inch tires and 3.23 gears, its still 3,100 rpm, put 29 inch on and you get 2,800. That still should work great with a 10 inch converter. So I'm really on the fence now, yeah from the light I be screwed but on the E way I can stay ahead of the pack yet be in the low 3000's and make good travel time to boot and if I wanna get better mph I could go 65 mph like 20% of traffic was going--I think a few jerks were going 60 or less, one jerk was in the 3rd lane out of 4 in some new tiny 40 mpg car, ah why don't you move on over to the right lanes if you wanna drive 55, some people I just can not understand. Hope they had no kids in that car, was an accident waiting to happen
 
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