Steering/Suspension Pull & Gears w/Posi Question

Two questions in one post.
The car = 77' Maverick w/302 4 Door & Power Steering

First up - I run on 17x7 wheels with low pro tires. When on the highway, the tires will pull the car left and right based on the ruts in the road. Kind of unnerving when going 55 and the car gets pulled to the side. Is there a way to tighten this up so the car doesn't do this?

Second up - I'm currently running a 3:55 Posi setup. I'm looking at upping the ratio and since I don't know jack about rear-ends, can I keep the same posi unit that's in and put a different gear set on it?

Thanks in advance

 

#1. Did you get the car aligned when you out the new wheels on?

 

Do you have a 8 inch or 9 inch rear-end?

 

The power steering is known to wander when it gets old.There is an adjustment to be made on the controll valve if you know how to do it (I dont) This may take care of the wandering to a degree. Low profile tires tend to follow the curvature of the road since the sidewall has less give than a standard tire so, keep this in mind. I would recommend an alignment as well as a good once over of all the front end parts.Good luck!!!
You can keep your current Locking diff and just change the gears on it but it will require professional set up to work well and live long...

 

Yep, I had a tech look all around and he couldn't find anything really. I think he said maybe replace the idler arm.. I got a box full of new front-end suspension parts that I need to get on eventually.


As for the rear-end, 8".

 

Thanks - The steering does have a slight wander to it. There's probably a half-inch to 3/4" of play in the steering wheel.

 

That Idler Arm could be most of the problem. That is the most common part to go out on our cars. Good luck.