I'd just start calling local junk yards and see what you can find. Best cheap performance option is another D16Z6 from any '92-'95 EX coupe/sedan or si hatchback. If your looking for dirty cheap, you can probably use any '92-'95 DX/LX engine as well, as long as you use the non-VTEC ECU, everything should plug in. I'd avoid an VX or CX as they both use different oxygen sensors than you stock EX setup (just wiring differences but why bother). You should be able to find a clean engine for less than $250 I would think. I'm assuming that the tranny/clutch is still good and it's a manual (not sure what would change with an auto, I'd stick wtih the same engine if it was).