It's not just swapping out a distributor. You would need to retrofit to a pre-EEC V ignition and that would not be worth it. Just get what you have fixed, what's wrong with it anyway?. The DIS system is superior to the pre-DIS ignition systems.
If you are after more performance I would consider making basic engine modifications along with a re-chip of your EEC V.
This is some of what it would take:
To drop the DIS you will need to to use an EEC IV (non-DIS) computer and wire harness set-up (you could probably convert your exisitng wire harness, or get one out of a T-Bird or Mustang). This also means you probably WILL NOT pass inspections.
You would need:
1) distributor (used say $60 from a 93 Mustang)
2) EEC IV computer (used say $150 from a 93 Mustang)
3) Wire Harness - Modify yours if you can, or get a used Mustang harness for about $100
4) Other misc EEC IV components???
5) You will also need to relocate the air temp. sender from its current location near the MAF, to the #5 intake runner on the lower intake manifold.
Result:
When you were done you would get the general performance of the Mustang EEC IV computer you select, which will not be a lot different from what you have now,possibly a little better preformance on the high end.
You can then start making performance upgrades.
In other words, you would spend about $300+ minimum and fair amount of your time just to get where you are today performance wise.
Take blk mk8 up on his offer for a better chip. You will be better off.