The original coating was pealing, so I didn't want to spray anything over; had to remove the old stuff first.  I tried a few different methods; dry (with a scraper), chemicals and finally; heat gun.  The heat gun with a 2" scraper worked really good.  I only removed the coating on the floor pan and elbow area.  Not the back seat area as it appears to be a different kind of coating and it was not pealing at all.

Under this original coating, you will see other kind of seams (roughly done mind you); those you don't take off.  That's what glues the floor pan to the body.  I'm really glad I took the coating off of mine; because I found 1 big and 2 small areas needing repair at the seams that I would have not seen if I had not removed the coating.  I would push on the floor pan with a finger and be able to see the ground at the seams.  It has cracked and separated.  An epoxy cocktail followed by some fiberglass patches did the job.

Then I sprayed the area with a beige rubberized spray coating (3 coats). (Non-asphalt based product unless you want the smell).

The step after that for me was to add some kind of heat insulation (on a budget); so I opted for this foil product sold at the big home renovation stores (reflectix).    I also purchased a carpet set that has extra rubber and extra jute padding on it.  That's where I stand now; I have not put back the carpet in yet.

Long story short; if your original coating is not pealing; leave it there and add some heat insulation; such as lizard skin (all the way up including firewall) and verify you don't have any separation at the floor.  You would want to fix this before you put the new carpet in!  The good news is that our floor pan (74) are not metal; so we don't have to deal with rust!

Steph.

I also did some work under the floor.  Years of oil leaking softened the factory applied undercoating so that scraped off easily.   On other areas I tried Eastwood's chemical undercoating removal spray but that didn't do anything.  So I used the heat gun and scraper again and got areas that were relatively easy to access.  Then I applied some "Zero Clearance" insulation above the areas where the exhaust pipes are.  Overall, it's a lot of work, but now it's done and I have moved on.  The car is still on jack stands so I can't offer any performance information.  Maybe I'll get it going by next Spring.....

They used a 3M brush on glue and yes it did have a High smell. They let that glue flash for quite a while also. We made Terry (my71T) put both hands in his pockets...just to be safe

Keep taking pictures!

ebo