jefferycar Posted October 14, 2013 Share Posted October 14, 2013 My 47 Buick 56C needs a taller gear to make her happy @ 60- 70 MPH SPEEDS necessary for traveling in todays highway traffic. I did some preliminary research, and it seems there is a 3.90 -1 ratio Buick had available in the late 40's early 50's. Can anyone confirm this and further inform me as to which models and years I need to look for? I am a automotive Technician/Mechanic by profession so I am able to deal with just changing the center section out (preferred) or changing the ring and pinion should anyone have somthing to offer for sale. Any help in this matter will be most appreciated.Jeff Link to comment Share on other sites More sharing options...
buick840 Posted October 14, 2013 Share Posted October 14, 2013 Hi Jeff,The 40's Buicks certainly could have done with a taller rear end and many have done it This has been discussed many times and there are lots of threads that discuss it.This just one thread that may help you .........http://forums.aaca.org/f165/1941-crown-pinion-change-351659.htmlIf you use the search option at the top of this page you will find numerous threads that will give you your answers.Hope this helps and good luck with the change over......................I'm sure you'll love the difference it will make.Regards Link to comment Share on other sites More sharing options...
Ben Bruce aka First Born Posted October 14, 2013 Share Posted October 14, 2013 Jeff, anything from 1940 through 1955 will change out. I changed the 4:01 out of my 1950 for a 3:36 from a 1955. Works great. Dropped third gear rpm's about 650. Ben Link to comment Share on other sites More sharing options...
Joseph P. Indusi Posted October 14, 2013 Share Posted October 14, 2013 The original ratio in your 1947 56C is probably around 4.45 to 1. This is a relatively heavy car so I would try a 3.9 or a 3.6. In my 1948 Special I have a 3.40 like Ben and it goes real nice. Just remember that while you can comfortably go 60-65 MPH, you still have to stop that big Super. The easiset is to change out the just the pumpkin and use your drive shaft and torque tube.Good luck.Joe, BCA 33493 Link to comment Share on other sites More sharing options...
old-tank Posted October 14, 2013 Share Posted October 14, 2013 The easiset is to change out the just the pumpkin and use your drive shaft and torque tube.Good luck.Joe, BCA 33493Don't even consider doing it any other way. 55 used a one year only rear pinion bearing and a housing to match, so other year gears cannot be installed and 55 cannot be installed in any other housing (other years may have similar problems). Also if installing replacement gears, it is a real pain to set the pinion on those things.Willie Link to comment Share on other sites More sharing options...
RivNut Posted October 14, 2013 Share Posted October 14, 2013 (edited) www.car-parts.comFill in the blanks for your particular need. They don't list a Super, but they do list Roadmaster (1979 and prior) I typed in 1947 - 1955 and found a number of his for 'rear end assembly' (RWD) You would have to call regarding ratios, etc.Ed Edited October 14, 2013 by RivNut (see edit history) Link to comment Share on other sites More sharing options...
jefferycar Posted October 15, 2013 Author Share Posted October 15, 2013 THANKS FOR YOUR INPUT REGARDS JEFF:cool: Link to comment Share on other sites More sharing options...
jefferycar Posted October 16, 2013 Author Share Posted October 16, 2013 I went to the "Car Parts site" and got a potential hit today Ed thanks much:cool:Regards Jeff Link to comment Share on other sites More sharing options...
RivNut Posted October 16, 2013 Share Posted October 16, 2013 Hope it works out for you.Ed Link to comment Share on other sites More sharing options...
Bill Stoneberg Posted October 16, 2013 Share Posted October 16, 2013 Be carful going too high with the ratio. I did that on my 1950 wagon and now it wont get out of its own way. Once it gets going its fine but low speed torque sucks. Link to comment Share on other sites More sharing options...
Barney Eaton Posted October 16, 2013 Share Posted October 16, 2013 I was looking at an old aftermarket parts book and they listed a 3:27 gearset, called them High Speed gears. I am sure the company has been out of business for years. Link to comment Share on other sites More sharing options...
FLYER15015 Posted October 16, 2013 Share Posted October 16, 2013 Come'on Barney, we need more information than that.What "parts book" were you looking in ?Maybe the "company" was bought by someone else and has some NOS stuff we have been looking for.Don't leave us hanging..................Mike in Colorado Link to comment Share on other sites More sharing options...
Dave_B Posted October 17, 2013 Share Posted October 17, 2013 Jeff, I have the center section from a 41 century with 3.9 gears. I would love to see them get used instead of taking up space in my garage. I'm not that far from you. If your interested let me know and we can work out a deal.Dave Link to comment Share on other sites More sharing options...
jefferycar Posted October 19, 2013 Author Share Posted October 19, 2013 (edited) Dave, Of course lets talk I can be reached by cell 609-458- 8963 or my shop is 609 267 5234 or give me your number and I can call you:oJeff Edited October 19, 2013 by jefferycar (see edit history) Link to comment Share on other sites More sharing options...
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