The guy I got it from sold alot of these, I haven't heard of any problems.The directions show a simple 4 wire hook up and dont mention a difference for 4-6-8 cylinder hook ups. If it dont work, I will stand behind it.

Red to +12v
Black to Gound
Green to - terminal of coil
Yellow to lights

I can hook it up to my car and test it out for you if you want.

The only reason I didn't use is, I wound up going with all Ford Racing and Phantom gauges and this didn't match.