Researching G-body Cars

[Researcher]

Hello guys!
I can't say just yet what this research is for but, your gonna like it... I've been working on this research for over a month. It's not been easy to confirm information I've found but, I know there are some of you car-guys that know these cars like the back of there hand and I would appreciate your feedback!

Using the Monte Carlo 78-88 as the base, What years are changes made to the Monte firewall, core support, dash?
Also, from the list below which of these A & G-body models have the same (with year changes) firewalls, core supports, and 'basic' dashes as the 78-88 Monte Carlo?
Thanks for any help!

Buick Regal (1978–1987)
Chevrolet El Camino (1978–1987)
Chevrolet Malibu (1978–1983)
Chevrolet Monte Carlo (1978–1988)
GMC Caballero (1978–1987)
Oldsmobile Cutlass Supreme (1978–1988)
Oldsmobile Cutlass Cruiser (1978–1983)
Pontiac Bonneville (1982–1986)
Pontiac Grand Prix (1978–1987)

 

[GP403]

Just out of curiousity, why does it only start at '82?

 

[Researcher]

Just out of curiousity, why does it only start at '82?

Good point GP403! I'll edit my OP to include A-bodies. Thanks!

 

[fleming442]

Their
There
They're
You'd think a "researcher" would know, but whatever.

All of the inner structures are pretty well the same. The pretty bits are what set the different models apart. You have to remember that these were made in the beginning of the disposable car era, so every cost cutting measure available at the time was employed.

 

[Supercharged111]

I've been meaning to hit a certain junkyard 20 miles from my house as he has a lot of classic stuff. My hope is to find an aluminum core support. To be clear, would that 78 or 79 core support fit my 83 Monte? I think that's a fitting topic here?

 

[fleming442]

I've been meaning to hit a certain junkyard 20 miles from my house as he has a lot of classic stuff. My hope is to find an aluminum core support. To be clear, would that 78 or 79 core support fit my 83 Monte? I think that's a fitting topic here?

Watch out for 2 headlights vs 4....

 

[Supercharged111]

Watch out for 2 headlights vs 4....

Good to know, thanks for that.

 

[64nailhead]

Good point GP403! I'll edit my OP to include A-bodies. Thanks!

I've never understood the change from A to G when 95% of the parts the same - beware of the wheel stud change from SAE to metric. AFAIC, a 79 Cutlass or Malibu is not what I consider an A-body - but what do I know?

 

[81Regal]

Firewalls are the same 78 to 88, floors are the same 2 door and 4 door with the exception of the El Camino where the transmission tunnel is shaped differently due to the extra length.
Radiator core supports are the same size, with the openings for the headlights being different.
Monte dashes are the same as El Camino, Malibu wagon and Malibu, the year breaks are 78-80, 81-85, 86-88, 81 to 88 are the same shape with a minor difference above the glove box.

 

[81Regal]

Buick Regal (1978–1987)
Chevrolet El Camino (1978–1987)
Chevrolet Malibu (1978–1983)
Chevrolet Monte Carlo (1978–1988)
GMC Caballero (1978–1987)
Oldsmobile Cutlass Supreme (1978–1988)
Oldsmobile Cutlass Cruiser (1978–1983)
Pontiac Bonneville (1982–1986)
Pontiac Grand Prix (1978–1987)

You might want to add Oldsmobile Cutlass Salon, Pontiac Lemans/Grand Lemans/Grand Am, Buick Century