MAF or not MAF

[U235a4]

could someone explain why some engines have the MAF sensor and other don't? Case in point my 05 F250 has one and my friends 05 F350 does not. just wondering why they would use the mass air flow setup on some and the speed density type on others?

[sinner6.0L]

i hear early 05s don't have one. the whole deal with the maf is that its purpose is to sense the change in intake air flow when the EGR opens up. it has nothing to do with fueling on 2004.25+

for some reason in early 2005(still under 04 emissions regs) the maf was deemed "redundant" with the deletion of the throttle plate and the addition of the up-pipe scoop.

i need to look into this topic a little further, that's about all i know. i don't know why they reintroduced it later in the year