Hi Guys:
I just finished my '74 last Friday.
I used a product from Pro Form, part number PF366.
It comes in a box with two sheets in it, giving you about 12 square feet.
Each sheet measures 29x32. It is a rubber based product, with an adhesive back.
Easy to put down NO!!! Was it worth the effort "YES".
The proper way to put it in is to use a heat gun and a small roller (I got mine from a hardware store, and it is used to finish wall paper joints).
You heat the Pro Form product (starting on one side and working a small area at one time, cutting to fit the area you are working on). Use the roller to ensure that it is pressed down properly and you work your way into the various nooks and crannies.
I've only done from the firewall to the rear seat on both sides. On top of this, I've laid down a product that is felt, with a reflective backing to help eleminate heat, and of course further sound deaden the interior.
From start to finish, with the interior having to be pulled out, and then re installed took me 10 hours, with lunch and supper time included.
Both my wife and myself, are so impressed, that I'm now going to buy another box, and do behind and under the rear seat. This should do the job for me, but by neighbor around the corner from me (who gave me the tip on the product), said that you can carry this even further, by sticking on the inside of your doors, and interior 1/4's. We'll see about that after the rear seat is done.
Total cost will be less than $150.00 Canadian.
I did a fair amount of reasearch before I laid out the bucks. There is the stuff the pro-audio boys use - many many $$$$$$, other products, such as the products at Home Depot etc., in my opinion were not designed to do what I wanted to do, they were primairly for insulating heating ducts and water pipes in your house. The stuff I used, is in MHO the best for the buck, and if I ever get that "62 440 hardtop I'm looking at, it will get the same treatment.
Hopes this helps you out.
transman