Install Cavalier/Sunfire seats
Comparison of both seats (sunfire seat on left):
Underside, seat track still on s10 seat:
First thing you need to do is take the seat track off the S10 seat. When taking it off, remove the nuts from all 4 corners, and take the nut off the L bracket on the side without the seat belt. On the side with the seat belt, you need to unbolt the L bracket from the side of the seat to keep the mount for the seat belt latch. You'll need to unclip the seat cover from the back and side with the seat belt so you can pull it back to reveal the bolts.
Two bolts on the side that need to be removed.
This is what you should have once you get it off.
Once you've done that, you need to cut off the bungs welded to the inside of the L bracket to clear the side of the seat. Below the bungs are circled.
Next you need to start drilling your holes. Start with the two front holes that are already existing. All you need to do for the front holes is drill out the threads so the S10 tracks will fit. On the back of the seat you'll need to find were the tracks need to go then drill your holes accordingly. I can't seem to get it right the first try, so I used a small round file to oblong the hole for the tracks to fit in.
Below are the holes drilled in the bottom of the Sunfire seat for the S10 tracks to fit.
Now all you need to do is put the tracks in the holes and tighten the nuts down. Don't forget to put the cross bar in so you can slide your seat foward/back.
Here's the seat tracks installed with the factory seat belt latch.
Thats pretty much it, they should now be ready to bolt into your truck. Here's my finished product ready to go in.