www.powerpro2000.com rebuilds longblocks for many Honda cars. Be very careful with doing this project-the cost will get you if you do not shop wisely.
For example the typical D16a6 for a CRX fully rebuilt goes for around $2100. You can get one with 100k on it for under $500, but no warranty of any sort. If you go JDM-get the complete package with tranny, axles, ECU, harnesses etc.