I do not understand the first generation determination. The '73 looks a lot different than the '65 so why is it still the first generation?

 

Are you talking about the First AND Second generation section?

 

Yea
Almost posted it there
First gen is 1964 thru 1973 but the cars are so different almost like 3 generations there

 

It is because it is grouped thusly.

'65-73 - 1st gen, because of this:
'74-78 - 2nd gen, the downsized years.
'79-93 - 3rd gen, the Fox years
94-04 - 4th gen, the SN95 years
'05-present - 5th gen, the S197 years.

The first gens are all sorta the same idea, just that Shinoda got a hold of them and blew them up in size.

It's about basic ideas that these generations are segregated, not actual models. If that were the case, then we'd have:

'65-66
'67-69
'70-73
'74-78
'79-86
'87-93
'94-98
'99-04
'05-09
'10-present.

Which is 10 generations. Semi-major to major body/interior changes define these. But that's my take on it.

Gotta make the breaks somewhere.

 

UP to '74 and the Mustang II, the cars were all Falcon based, and many chassis bits interchange, even if the bodies were different. And since the Mustang II is, well, the Mustang II, it would be even more confusing to call it the 4th or 5th generation Mustang when it's clearly the 2nd generation.

64-66
67-68
69-70
71-73
74-78

Yeah, that's just too many when the '64-73 share the basic chassis (widened in '71 to accomodate the 429 engine)