I am assuming this pad was used for heat suppression or sound deadening. Were the used throughout the series?

my late 72 has one.

The pad style changed in later model years, went to a full size pad that was the same dimension as the rear trunk carpet. I can add a picture tonight.

My '74 has the full style trunk pad beneath the carpet. In places, I think it's still tacked into place with some kind of adhesive. It even covers the jack storage location, but it's flexible enough to pull upward to access the jack.

I don't spend much time in the O&H forum, so I should add: My car is a bit of a time capsule, but extensively driven. It's a 1974 2.0 in Saturn Yellow with brown interior. It's never been restored. AFAIK, everything is original except induction system (FI was long gone before I owned it) and heat exchangers/exhaust (some PO put on a Monza/Manta). It's been resprayed (low quality job) in the original color at some point, and some rust rehab was done in the hellhole and longs. Rocker covers are stock-style Stainless steel, powdercoated matte black.

Some of the factory markings (e.g. top of the strut towers in front trunk; steering wheel) are still visible.

Eric,
Was was the composition of the later pads? Believe they started in late '73.

Was it still a foam core wrapped in a vinyl sheath?
Pat

Pat,
My 73 has the larger pad. Mine is not wrapped in a vinyl sheath (I've seen the vinyl wrapped ones for sale)--it's just black very heavy molded foam about an inch thick, that is smooth textured on top and bottom.

I think the purpose was just to hold water in order to rust out the rear part of the trunk.

If everyone refers to their copy of Johnson's authenticity book, you will find your answer. They got it right on this one. Three different pads.
Don

Rear Trunk Pad 1974 MY (Prod 10/73) Pad is roughly the same dimensions as the carpet that covers it. Material is a dense foam with a smooth coating.

Click to view attachment

If anyone is looking for on I have one for sale. It is like Eric's picture above.
Thanks
Van914

PM sent....

they stopped in 72..73 started the ..'Molded' pad.....

Ditto.

Here is the pad from my '76. It's a very thin vinyl covering over soft and pliable foam approximately 1" thick.

Click to view attachment

My 10/71 1972 has the pad as pictured in the first post, as did my previous 1971. I agree with the comment that they just seemed to support moist conditions for rust directly beneath them, like a covered sponge.