OldRide Answers Home
Using OldRide Answers
Ask a Question
Browse Questions In:
Other Makes
Classic Trucks
 General Topics
General Questions
Help Identify
Classic Car News
General Restoration
Vehicle Maintenance
Site Suggestions & Comments


Ask a Question in OldRide Answers
Help Enrich the Classic Car Community
Explore Closed Questions and Answers
 Search Questions: 
I have a new project 1969 chevelle.what rear gears to run with.
I have a1969 chevelle I bought that was under constuction.The car has a new built 454 at 500 hores the motor is very strong and built. the transmission is bad.I have a turbo 400 short shaft transmission out of a pickup that was a stong working trans,I will be putting it in place of bad trans in car now.I purchest a 12 bolt rear end but gearing are hight 2.71 I like the Idea of high gears but worry this will heat up trans or be hard on motor.I realy wanted a cruser car but the power is nice to .What gear would best work and what rpm rang would the moter run at on high way at 70 mile per. hour with 2.71,3.73,. I no the 10 bolt will not be strong enough so I need to put this 12 boit in its place any info would be great thanks.
what rpm rang.
454 turbo 400 2.71 gears run at 70 mph =
454 turbo 400 3.73 gears run at 70 mph =
454 turbo 400 4.11 gears run at 70 mph =
454 turbo 400 4.56 gears run at 70 mph =
posted: January 11, 2009
  Answers (4)
The other things you really need to factor in are the diameter of the rear tires ,most important what range is the cam in that engine going to be doing its best pulling power a range of say 2,500-3,500 at 70 mph then that is what you are going to want shoot for so it will stay in that sweet spot,asuuming this is going to be a street car.

3.73 is a good all around gear, you drop to 4.11s and you will be screming on the highway at 70 MPH.
posted:  January 11, 2009
Click to close this picture
i am sure their is some complicated formula for figuring these things out, but from experiance i can tell you that with a 3.90 axle ratio at 70 you will be turning close to 3200. use 3.73, best bank for the bucks, good cruising speed yet plenty of quick grab! 4.11 and up is great if racing is your only concern but it sounds like you want to enjoy the car a bit also.
posted:  January 11, 2009
Click to close this picture
One nore trick to do with that 400 turbo, go to your Chevy dealer and get a governor for a 1970 L-S6 Chevelle with a 400 turbo,that is slicker than snot on a marble,and will have some guys wondering what has been done to that transmission!!
posted:  January 11, 2009
Click to close this picture
hi looking @ what you got there is still good , go this way leave your 10 bolt in there change your carrier to 410 put a 7ooe auto in there.these are good tranys and will handle the power while changing your tranny do the convertor to what you ,, this way you can race or cruise and have gas mileage .ihave 428 pontiac 550 10 bolt 11.5 quarter ha ha ha
posted:  January 13, 2009
Click to close this picture