Firewall pad on 66 GTO
 

Duh. Forgot to make a note of this when disassembling the car. Now test fitting the firewall pad from our host(the pricey one) prior to gluing it in place. Based on my other cars, it appears the carpet is intended to tuck up under the lower edge of the firewall pad, so I should not glue the lower two inches or so of the firewall pad. Does that sound right?

The firewall pads are not glued on. They are held in place with the round push i n clips and heater box etc.

...and you want to use the old fasteners if you were able to save them. The new ones(several years ago) were made of a much harder material and would not work...I ended up using the original fasteners...(softer rubber material).

X3 No adhesive,
as mentioned the OE thick rubber pad retainers are the BEST.
Making/using a push tool for them is recommended.
Removing the Cutouts helps with alignment.

The Repro Plastic Retainers SUC!

Help is not necessary but is always a good thing.

Getting the top of the pad set in first then allows you to move the pad around slightly to align the cutouts,
and then working on installing the heater box before all the lower plug retainers.

Firewall pad on 66 Gto
 

Okay, I’ll forget the glue. I’m familiar with the pad retainers. I have the better quality rubber ones and I’ve already tested getting them inserted with a push tool I made up. Yes, the plastic “Christmas tree” version is truly lousy. So, back to the original question: does the leading edge of the carpet tuck under the lower edge of the firewall pad?

Can't say with 100% authority but since the Carpet goes in after the Pad,
I have always installed it over the Pad.

The plastic Foot shield/guard at the base of the column is what prevents the Carpet from rolling over/down.

Right or wrong never had any issues.

I always tuck the carpet under the pad. I had several original carpet GTO's and they were tucked under.
It also makes for a nice clean line.

FWIW
 

A shot from the recent "Survivor" on Hemmings;

https://live.staticflickr.com/65535/...11b4e90f_c.jpg