Whoa ... I didn't think the sound deadener under there weighed any more than 20 lbs. tops. Did you put down the carpet without any kind of padding or anything under there to shave off 60 lbs.? I'm thinking of actually keeping most of the interior as-is on my '84. I just need to either paint or redo the headliner, since all I've got up there is the cardboard/fiberboard backing right now, and maybe get a PROPER set of front seats (instead of two passenger seats). The feeling of riding around in a fully stripped car that rattles and squeaks and resonates like a tin can on wheels gets kinda old after awhile - I'd kinda like to have SOME kind of sound insulation and comfort. Thinking of ditching the A/C, though, so that'd be 20+ lbs. or so right there ... and if I get off my arse and exercise a bit, I could lose another 10 lbs. off myself...
Yes...carpet and all the padding and the tar sound deadening crap under that, and the carpet padding was wet. I don't know why because i've never had a window leak or anything...probably just condensation. The carpet wasn't wet to the touch, it was just down underneath in the padding and it STUNK.
I didn't weigh the carpet and everything, but it did take 2 people to carry it to the dumpster. The 60lbs is going by the first time i weighed it minus the second time i weighed it which was right after the carpet came out. In all reality it could also be that there was less gas in the tank the second time around.