ok gurus,taking the plunge and swapping th400 for a super t10.I am looking for advice/opinions on rear end gears.Trans. has 2.64 1st,rear is 2.73 open,tire size is ~26".I have no experience with this combo,but i am sure i will need a change.71 chevelle with a mld 454, mostly around town and very little extended hiway miles.After reading posts on this this forum i am considering waiting and geting a 3.31 gear set when available this fall.Any advice/opinions are always welcome.I will post pics. after swap hopefully in the next few weeks.Thanks in advance

The 2.64 1st gear Super T 10 is a very popular sought after transmission.Go with 3.42s in the rear and the car will still have a little umph off the line and highway driving will still be tolerable.I have the 2.64 Super T 10 with 3.73s in the rear,and it takes off like a bat out of hell.I do suffer a little bit more on the highway though as compared to 3.42s in the rear.Its so hard to find that perfect combo(Take off torque,highway cruise gear)The ultimate way is to have low 1st thru 3rd gears in the tranny,4th gear 1:1 and have 3.08s in the rear.That way youre only in the tranny gears temporarily and when your in 4th,everything gets relieved.Theres 2 ways to look at it,build or buy worked tranny with low gears and run with highway gear in rear.Or get overdrive tranny and have low gears in rear.1st option,IMHO is better because rearend aint getting overheated and worn out quicker as opposed to 2nd option where you get the relief on your motor and tranny but rearend is screaming to keep up with you and then the overheating and wear and tear process starts to take over.Its and individual decision.

I've spent way too much time staring at gear ratios, I even made an excell spreadsheet that calculates speed and rpm and rpm drop. What I've noticed is that no 4 speed transmission that I've seen will give you what a 5 speed with overdrive will. Even your T10 with 3.45 rear won't have an as highway friendly final as my T5 with .68 5th and 4.11 rear. And if you use a 3.08 or numerically lower rear you will get the freeway fuel economy but your 1st gear will be like my 2nd gear, which will hinder initial acceleration and possibly wear clutch faster.


This link should allow you to download my gear ratios spredsheet.
You need MS Excell. Its pretty easy to use, everything in red you can change and it calculates things for you. Good luck.

http://www.mediafire.com/?7g9xng0yx3y

I hear ya man.As for me,no overdrive for me with killer low gears in the rear.I will keep the lower tranny gears with the hiway gear in the rear any day of the week.