1. steve from staten island

    steve from staten island FBBO Gold Member FBBO Gold Member

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    My car is on the road after all theses years. The engine is a 383 completely rebuilt and the rebuilder figures 330 to 350 HP. I have a open 8 1/4 rear with 2 something highway gears.
    I had the car on the highway and had it up to maybe 55-60 and it felt like the engine was at a fast idle, it just cruised along with no effort. It felt strange as I hardly was pressing on the gas pedal
    I have a sure grip 355 rear that will be rebuilt shortly and I wanted to install it in this car.
    My question is would I be better with changing the gears to 3:23? The current rear is the only component I didn't rebuild or even inspect in detail so I figured id use the sure grip and rebuild that and I don't mind the added expense of a new ring and pinion.
    Any opinions are welcomed and appreciated
     
  2. Curiousyellow71

    Curiousyellow71 Well-Known Member

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    It depends some on how tall your rear tires are. If your running a tall tire 3.55 can help make up for it. If you have a short 14" tire then 3.23 are comparable to tall tire/3.55s.
    3.55 are a nice performance gear...and a 383 is going to like it. If you do lots of interstate 75 mph driving 3.23.
     
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    • biomedtechguy

      biomedtechguy Accelerati Rapidus Maximus FBBO Gold Member

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      3.54 gears had my 440 spinning 3,500 RPM at appx 72 mph. That was tolerable on the 2 hour trip to Alabama for an annual show,
      BUT
      2,750 RPM is so much better now that I have a 5 speed.
      SO
      for your situation, you may find the 3.55 turns a bit too many RPMs at 70 mph
      BUT
      it may also be tolerable, and is a great performance gear unless you are going to spend a good bit of your driving time at 70 mph. Then you may want to consider 3.23
       
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      • BDF6

        BDF6 FBBO Gold Member FBBO Gold Member

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        I ran 3.55 w/26" & 27" tires for 3-4 years and that was great around town & local or short trips. After 2 long road trips with those gears I went back to 3.23 & 27" tire and can cruise on the freeway for distances now without a problem. I spend a lot of time in the slow lane though at 70 mph.
         
      • HEMI-ITIS

        HEMI-ITIS STREETER on LI FBBO Gold Member

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        I drove around with 5:13 gear and a spool for many years.On the LIE I was in the right lane going 50..........
        You need to decide if you want the red light take off or the cruise at 70.
         
      • Darter6

        Darter6 FBBO Gold Member FBBO Gold Member

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        3.23 is a all around good gear. I always look at your driving environment.Local roads mostly ? or freeway drives ? For me in 3 miles any direction the speed limits are between 65 and 75 MPH. I pulled 2.76 gears out of my 64 and installed 3.55.It felt like I had 5.13's in it after the change. It all depends on where ya live and how you drive.
         
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        • Beach Goat

          Beach Goat Well-Known Member

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          Really you aren’t going to get stellar fuel economy no matter what you put back there...the difference between 3.23 and 3.55 might be 1mpg? So would you go from 19mpg to 18mpg to have more fun off the line? Almost everyone I’ve ever heard talking about gears regrets going low, but almost no one regrets going high (numerically).
           
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          • bee71

            bee71 Well-Known Member

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            3:23. Good enough for start off the line nice cruising.
             
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            • 33 IMP

              33 IMP FBBO Gold Member FBBO Gold Member

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              Steve, if i was you, after all these years, i would just drive the heck out of it and enjoy it for a while before I messed with it again!
              That said, do you know what your current ratio is. It sounds like it might be a 2.76 (fast idle at 60 mph). Its kinda important to know where you are, to know where you want to go. 2.76 to 3.55 might be too far in the wrong direction , 2.94 to 3.23 might be so little change you might regret the expense .
              Next question, what 8 3/4 pumpkin do you have, 741,742, or 489? It's important in case you decide to change the gears. Each case has limited gear choices available .
              Now to get to your actual question (it's about time, i know). I would use your 3.55, because you have them. If it seems like it revs too high, tall tires on the rear can alleviate that, as has been said here before. That said, i think you would prefer 3.23. It's an excellent compromise gear. Compromise isn't always a bad thing. It gives good dig around town, and reasonable revs on the highway.
              Here's where asking which number pumpkin you have comes in. You will have to research your case number to find what gears are available for your case.
              Now for personal opinion. I find myself making frequent trips of 250 miles lately, and my late model stuff is around 2100-2200rpm at 70-75 mph. That is about what everyone seems used to. Close to that is what most people would like, out of their collector car too. It sounds like you have that now.
               
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              • 69Bee

                69Bee FBBO Gold Member FBBO Gold Member

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                My '69 had a 3:54 Dana 4-Speed, and I drove it across the country from AZ to MD at least twice, and 2 years in Germany on the autobahn (130+ MPH), and never had a care or issue. Gas was cheaper, so I didn't care about fuel mileage. I did not have a tach, but the engine RPM never gave me any concern, even in Germany. I believe I was running about a 26.75" tire at the time. Personally, I feel the 3:54 is more preferable than the 3:23, but that is just me. If I ever find the project car I want, it will get a 4:10 as I am going to use a 518 Auto behind a '55 331 dual quad FI Hemi. :thumbsup: Looking for a '33-'34 2 dr Plymouth Coupe.
                 
              • Dajkzo

                Dajkzo FBBO Gold Member FBBO Gold Member

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                Hi Steve,

                I just switched from 3.91 to 3.55 with the 383 currently in my car along with an A833. I really like the 3.55 around town and on the secondary highways. On the interstate it’s 3100+ @70mph with 26.61” tires (295/50x15).
                 
              • Fran Blacker

                Fran Blacker FBBO Gold Member FBBO Gold Member

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                3.55's would be my choise. Ran my car out to Niagara Falls. 350+miles 27" tires 3300/3400 rpm 70 mph. Had an 64 Olds Starfire came standard with 3.55's.
                 
                Last edited: Sep 17, 2019
              • PurpleBeeper

                PurpleBeeper Well-Known Member

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                Hey Steve, just make sure....YOU HAVE A 8-1/4" right? and not a 8-3/4"? If so, I STRONGLY recommend you change the whole rear end out or that 383 will spit the guts out of the 8-1/4" about the 3rd time you floor the car from a stop & get good traction....seriously.

                As for gears, these guys are right.... 3.23/3.55 are the best overall cruising gears & tire height does matter too.
                 
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                • biomedtechguy

                  biomedtechguy Accelerati Rapidus Maximus FBBO Gold Member

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                  To add to what I posted, the 750 less RPMs that I have now, because of the combination of the 5th gear overdrive ratio and the :thumbsup: 4.10:bananadance:Ring and Pinion gearset that I switched out the 3.54 gears for, those 750 less RPMs make highway driving WAY BETTER than the number would suggest. A lot less noise, a lot less worry about something breaking or excessive wear. The beautiful thing is that now I get the eye popping acceleration of the 4.10 gears (and the 3.54s were impressive already) and the benefits of less RPMs in 5th.
                  If I had a "highway star" like a Superbird or spent a lot of time on the highway, or did power tours and the like, I may have kept the 3.54s, maybe, with the 5 speed.
                   
                • Sixpactogo

                  Sixpactogo Well-Known Member

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                  Wow! 3.54 gears on the autobahn? 130MPH+? That would have given me great concern. I don't know how tall of tires you have on that Bee but I would think you would be turning close to 6G's. I can't imagine any of my big blocks staying together for long running those kind of RPMs for very long. My 69 383 4 speed Bee had 3.55 cogs with 14" tires back in 69. I had the speedo up to around 140 a few times but who knows what the actual speed was. I don't think it would have survived the autobahn.
                   
                  Last edited: Sep 17, 2019
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                  • 1 Wild R/T

                    1 Wild R/T Well-Known Member

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                    Something worth considering... A 500 rather than a 518, the 500 has a lower 1st & 2nd gear but the same 3rd & 4th...

                    So if you were to use a 3.73 axle 1st would slightly numerically high, 2nd would be virtually the same & 3rd & 4th would be taller... Plus the 500 is a little smaller but can built to handle plenty of abuse...

                    Oh btw a 3.73 with .69 O/D = 2.57 2000 rpm’s = 65 mph
                    A 4.10 with .69 O/D = 2.83. 2350 rpm’s = 65 mph
                     
                    Last edited: Sep 17, 2019
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                    • Jcharger

                      Jcharger Well-Known Member

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                      3.23 will be nice, but if it were me, I would go with the 3.55. It will be more fun.
                       
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                      • Dan64

                        Dan64 Well-Known Member

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                        Steve,check out Wallace racing speed/gear calculator ( lots of good calculators on that site).
                         
                      • threewood

                        threewood FBBO Gold Member FBBO Gold Member

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                        My 62 Belvedere has 3.23s and my 69 GTX has 3.55's. If you drive on the highway a bit the 3.23's are going to be better. If you are more focused on performance the 3.55's will be better. Like others have said, cruising down the interstate over 3k on the 55's.
                         
                      • 67440chrg

                        67440chrg Well-Known Member

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                        I have 3.55s in my Charger with 275-60-15s and I like it. If I remember right it runs just a hair above 3000 rpm at 70mph. As long as its not to loud its fine. I like the power from a stop too.
                         
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