Where is a good place to get a rear sway bar?

http://www.p-s-t.com/ they have larger front ones too

That's where I got my front end kit, but I didn't notice any rear sway bars only front, I'll recheck thx.

http://www.addco.net/index.shtml

If your interested, you can mount a front bar on the rear, but suggest you have a heavier one on the front, if you don't aready.

I have a 7/8ths on the front. Is that large enough? What would be a good size for the rear? I was thinking 3/4.

Use the stock size front bar on the rear. There are not a lot of choices except the same size both ends but that is not recomended under ordinary circumstances.
To mount, use axle size muffler clamps around the housing. Use front frame mounts and urethane bushings. Work the mounts to bolt onto the clamps.
The bar ends come out centered and in line with the frame just in front of the rear axle. Fab link mounts, make up your link assemblies. When mounting, adjust the axle mounting points to clear all areas and allowence for vertical motion of several inches each way. The axle clamps will end up at an angle to arrive at the best fit. The closest point will be near the right lower shock mount but will clear without a problem. There is no alteration done to the bar.