rear gear ratio question

I have a ford 8 inch rear when I jack up the car and turn the drive wheel one rotation forward I count 1.3 rotations on the driveshaft what would this put my gearing at???? 1.35 is this a real gear ratio or am I doing something wrong????? I cannot find any gear close to this number I am confused now....

 

Are both the rear wheels off the ground when you are checking this?
Also does your 70 have the 7.5" (removable rear cover) or 8" (drop out center section) rear end?

 

drop out center section 8 inch and yes both wheels are off the ground...

 

There should be a small metal tag on passenger side, attached to one of the bolts.
It will have you ratio on it....that is if it isn't gone or someone left it there and did a r/p swap.
Robert

 

I must be doing something wrong I am running highway speed 65-70 at 2500-2700 rpms that would put it at 2.79 I don't know what I am doing wrong but as usual nothing comes easy for me.....

 

2:79 2:89? and 3:00 were the gear ratios offerd in our cars so you are probably running the 2:79's like you suspect.RPM and speed coincide with your observations also so yeah 2:79's it is.Unless you are running a tire that is taller/shorter than stock.

 

You need to only let one wheel turn. That would make the driveshaft move about 2.79 times around.

 

Have someone help you with this, it is easier if you both count. With both tires in the air, rotate the driveshaft. Have one person count off 10 rotations of the tire while you count how many rotations of the driveshaft. Then divide that number by ten.

If you get 27 spins of the driveshaft, you have a 2.79.
If you get 30 it is a 3.00.
If you get 35 or more, you get a lot more fun ...

 

only 2.79 & 3.00 were available in 8" rear ends in Mavericks/Comets 71-77