OK - Just like the title says, I have a 1987 Trans Am.
It came stock with carb'd 5.0 in it, stil have stock rear end.

Is this rear end POSI and what stock gear ratio? I got the car with no motor/trans so I am currently building a SBC and 700R4;
this will be done soon so I am scattering to get the rest of the car ready.

So, if NOT POSI, is there anyway I can have it rebuilt to be posi and modify the gears.
Also, is 3.73 gears really that bad on the highway with a 700R? should I: go 3.23?
Or, would it be cheaper just to go find a rear end with posi and gear ratio I want?

 

https://www.thirdgen.org/forums/tran...-10-bolts.html
Did you read this?

 

So there is no way to find out without looking under the car?

 

Awesome info thanks!

 

Here's a link to a 10 bolt build =
https://www.thirdgen.org/forums/tr...de-photos.html (10 Bolt upgrade photos)
Here's a link to L.P.W Racing that I found very helpful when deciding on a "Support Cover".= http://www.lpwracing.com/Diff_Cover_...omparison.html
here's were I bought it.= http://www.jegs.com/i/L.P.W./619/301-7.5G/10002/-1

I’m not saying this approach is for everyone. There are "less"and then there are "more" expensive ways to do it.