time to change my rear end??

My 65 with 250 and recently installed turbo 400 is shifting very early and at 50++ its really humming, like it needs another gear or overdrive. Took it to a tranny shop they said its the rear gears ,they are for low speeds,. I am not sure whats in it, yet, but what gears would I want ?? hiway cruising??
I have several old differentials to check but I was wondering what gears you boys are running and are happy with?? I guess there are many different combos used in the earlys?? Merry Christmas to all of you!1

1st.=check the shift adjustment-then the vacumn modulator?? What gear ratio do u have ?? must determine this 1st. If u have to change the rear=??? id think about what im doing with the van-towing much? loaded heavily/ empty usually- remember these vans are just like boats (no-pun!!) and we forget what were puttin them. parents 3 kids camipng stuff, water, foods and all- gets heavy? id use at least 3;23 to 3;73 ratios and a posi type > might look into a later van rear end also?? Have fun.

I just changed mine last week went from 3:73 to a 3:08 and man what a difference!! Now I have to adjust my speedo.

I guess the ratios are a little different on G's but my Dodge had a 3.55 in it with a 3-speed manual, I was turning ridiculous rpm's at 55 mph. I put a 2.94 gear in it and now I'm pulling 2500rpm at 55mph which is tolerable.

I'm running 14" rims with 60 series tires and am going to switch to 15" rims and 70 series tires to get me down to about 2000 rpms at 55 or so, that will be "comfortable"

I still have the OEM 45 year old 273 engine, don't want to be stressing that baby any more than I have too. Also, I'm looking more for comfort than speed with this van, I've had hot rods/drag cars before, this is my mellow machine

Here's something for you guys to play with. http://www.corral.net/tech/gearcalc.html

this will help too

http://chevelleengineer.home.comcast.net/~chevelleengineer/speedo.htm

and
http://www.angelfire.com/fl/procrastination/rear.html

[quote="Van Halen"]I just changed mine last week went from 3:73 to a 3:08 and man what a difference!!


So you love the 3;08?? I am hoping for low rpms at 50-65 mph. Right now its like driving in low!! I have a shop looking at it he is sayin 3;08 0r posi??

im running 3:08's with a 230 and 3spd, really like the way she drives no problem passing, runs 65-70 no prob. most of the time i run 60 cant think of any reason to drive the brick any faster than that.

Ok its a 4;10 with bad waxles. so we are looking for axles and probably go with 3;40posi???$$$