For tires, 205 or 215 is about as wide as you can go without getting into clearance problems. A 215/75-15 will give you a diameter of 27.7" versus the 25.4" of the stock 185-14 tire. Just remember that you should have at least a 6" wide rim to support that section width, and 6.5-7" is even better. That size tire has a load rating of 100 (1740 lb), 30% higher than the stock tire size.

You will indeed have a speedo/odo error, about 10% if you use the 215/75-15. Your speedo will indicate lower than your true speed, i.e., you'll be doing 66 mph at an indicated 60. I think your vintage Brick uses the mechanical speedo, and a speedometer shop ought to be able to change the drive gears at the tranny end to get your speedo more accurate.

The rear axle is a Dana 30 (also used on the front of many Jeep models), and lots of gear ratios are available, although not from Volvo. I think the stock rear axle for the auto trans 3.73; with the taller tires you would need to go 10% higher (numerically) to get back to where you were, so that would be about 4.1 or higher. Try a 4WD shop for a different gear set, and maybe even look into a limited slip (I love mine). I have seen listings of gearsets up to 5.38 for that axle, so you should be able to find something that works for you.

You are wanting to lift the rear several inches.

Then do that...

I have a 78 242 - the rear was "sagging" so I dropped in a set of rear 245 springs. This stiffened up the rear - but did not raise it - but now the rear does not "wallow" and even with a full load - the car sat level.

But I wanted to lift the rear about 3".

So I did - I built lift blocks from 3" "C" channel iron - welding two pieces edge to edge to make an open ended square box.

This gave approximately 3" of lift at the rear. The rear sits higher and looks great.

Then to lift the front - I finally found and installed front coils from a diesel 240 (the heaviest engine of the 240 series). I also installed a new set of KYB strut cartridges at the same time.

This raised the front about 2.5" Not as much as I had hoped - but better than before.

Now all I need to do is line up a set of 15" wheels, run higher profile tires, nd ensure that the fenders clearthe tires, and my rally Volvo is set to go.

Good luck with your project.

Ask the guys over at NAXJA.ORG [North American XJ (Jeep Cherokee) Assoc. They're always lifting and usually have to have 'custom' springs made. Let me know what you end up doing. I want to do the same with my 245. I was about to order some of the iDP OL springs before I read this post, I think I'm going to wait. I do have 215.70.15's under my 745 that gave me a little height and helps out a bunch on the freeway too.

Michael

Ask the guys over at NAXJA.ORG [North American XJ (Jeep Cherokee) Assoc. They're always lifting and usually have to have 'custom' springs made. Let me know what you end up doing. I want to do the same with my 245. I was about to order some of the iDP OL springs before I read this post, I think I'm going to wait. I do have 215.70.15's under my 745 that gave me a little height and helps out a bunch on the freeway too.

Michael

Well-my 2 cents is to put in those hydraulic shocks that you can control like the "low-riders" do--you can adjust height etc to your needs. If you consider it-I think you need to be prepared to lay out a chunk of $$$$. That's my 2 cents--prob worth only a penny--and winding up with change-----