Hello all,
So while looking through threads I found a thread about timing, and someone had asked if the guy had Mass Air Low or Speed Density style, I don't know the difference or how to tell the difference. I have a 1985 IROC with a 5.0 liter "F"
Pictures are worth 1000 words.....
Thanks

 

Your 85 has a MAF.

"Mass Air Flow" sensor (85-89), typically called a MAF, or MAS for Mass Airflow Sensor measures the amount of air being drawn in to the engine. It is a fairly large housing (compared to a MAP) that is locate in the intake/aircleaner tract.
Picture here.
Or just here:




Speed Density (90-92) uses a MAP sensor = Manifold Absolute Pressure. This measures the pressure (vacuum) in the manifold and calculates how much air is flowing into the engine. It is mounted on the passenger side rear of the plenum:

 

Wow that's great!!! The pictures sure do help, I really do appreciate it.