I have a 90 firebird formula 305 tbi. when I bought the car the guy who sold it to me said it has the MSD ignition, which it does because I can see the box, but I later discovered that it isnt wired up. So I was wondering if anyone can explain to m ehow it wire it up.

its the MSD 5, and there are 3 wires coming off of it, red, white, and orange

 

MSD has the instruction manual online http://www.msdignition.com/pdf/pn_5200.pdf . Red goes to coil positive, orange goes to coil negative, black goes to ground and white goes to ignition trigger.