What year is this Firebird? | A question for the experts

Big window, big scoops. I'm gonna go with 1975. Unless it's a later car with an early nose. 
 

Love those Formula hoods!

Mutt?  Later rear with an early nose?

Seems like a '75 or later car with an earlier front clip swapped in due to the front bodywork not computing with the big back window.

And I'm embarrassed that I didn't notice the rear window at first. A friend mentioned it when I posted the photo to my FB. 

And a related question: Camaros and Firebirds share the same line for E Street Prepared in the SCCA autocross rule book, meaning you can swap back and forth. So, why not mix noses and tails? 

"So, why not mix noses and tails?" - because explaining an Olds 403 in your Pontiac is hard enough, having to explain it in your Chevy seems like it would be worse (which actually makes it better).

David S. Wallens said:

And a related question: Camaros and Firebirds share the same line for E Street Prepared in the SCCA autocross rule book, meaning you can swap back and forth. So, why not mix noses and tails? 

Editorial Director, Grassroots Motorsports & Classic Motorsports

I like it.

But how easy is it really? Are the fenders similar enough to allow the other's bumper to fit? Or if you have to change fenders, would they match up with the doors, etc.? 

JG Pasterjak said:

David S. Wallens said:

And a related question: Camaros and Firebirds share the same line for E Street Prepared in the SCCA autocross rule book, meaning you can swap back and forth. So, why not mix noses and tails? 

Editorial Director, Grassroots Motorsports & Classic Motorsports

I like it.

But how easy is it really? Are the fenders similar enough to allow the other's bumper to fit? Or if you have to change fenders, would they match up with the doors, etc.? 

I was thinking that you'd swap front fenders along with the nose (because I'd want the T/A fender scoops). 

As people said, wrap-around rear window = 1975-81. Without seeing the tail pan, it's tough to tell. Looks to have the smaller 3-piece rear spoiler (1979-81 got larger ones), but these things are like Legos and interchange. Hood is aftermarket, since it has that weird bulge in the middle, but styled after a 1970-75 Formula hood. That's no help, either.

The rear bumper might be a clue. The 1975 has a bumper like the earlier cars, while the 1976-78 has a urethane bumper cover. This looks like one of those. 1979-81 has a different one that incorporates the license plate holder and has a different side profile than the 1976-78 cars. It could have been changed, but I'm guessing they "run what they brung" here.

So, without seeing anything else, my determination is that this definitely a 1976-78 Firebird. Maybe even a Formula.

Flat nose Firebirds with the 1970 redesign.  This nose is from '70-72 time period I believe.