s10 to 49 olds
If you have room, go for the 9 inch.
Check out the wiki on the cavalier rack install. One issue is the length of the steering arms. To get them in sync with the rack travel I used Chevelle front steer arms and flipped sides to make them rear steer (slight grinding to fit the spindle but I may have had to ream them to fit). If you use the stock chevy arms they are too long and will reduce your turning radius.