DC tac hook up..?..

@halifaxhops has helped me tremendously.. the problem is I just don't know if I'm ready to pull the trigger on near $500 worth of parts to make this tachometer work.. I can see where eventually I would want to get the parts together for it put I just don't know if I'm really wanting to switch up my ignition system to accommodate it... It's quite an investment for a $50 tach I got off of Craigslist several years ago....