Difference between mass air meters!

[mustanggt94]

I know there are two types of mass air meters....draw through and blow through. I just bought a used Pro M mass air meter and I can't tell if it's the right kind. Is it physically any different? My Model number says 80C and the Calibration says 19C. What exactly does this mean? I am going to use the tweecer to tune it but I need to know how it's cal'ed first. Thanks!

 

[2000xp8]

You'd know if it's a blow through, it would of been very expensive and definetely metal. Blow throughs are for pro charged mustangs mainly.

19c is likely the calibration for 19lb injectors.

 

[millhouse]

Blow through maf's are used on anything which compresses the air before it reaches the the maf.