Rb20'd S13 Digital Cluster Help!!

[Spitfire8o5]

I have an 89 se 240 coupe w/rb20det w/ factory HUD and digital cluster but nothing works except for the temp. I was wondering if I need to modify anything or get a specific cluster.. I haven't been able to try another cluster because all of my friends have the regular cluster.. If anyone could help it would be appreciated.. I would like to know how fast I'm going, and how much gas I have at least haha

thanks in advance..

Roger