Best way to cover holes in firewall with the car together?

[Vicinity]

I didn't realize I'd only use a few of the holes in the firewall after I get everything finished up, now I have a bunch of open holes in the firewall leading to the passenger cabin. Whats the best way to go about covering/filling these until I take the front back off to weld them closed?

I'm going to install a VA heater core unit at the end of the year, so that's when I'll be welding it up, it's gotta last at least that long.

[dontlifttoshift]

Those little chrome plugs that they sell at the hardware store work well for a temporary plug. They have black plastic ones, too. A little bit of strip caulk can fill some big holes for a while as well. Got some scrap dynamat? Stick it on from the backside. There are all kinds of ways to get by.

[Vicinity]

Those little chrome plugs that they sell at the hardware store work well for a temporary plug. They have black plastic ones, too. A little bit of strip caulk can fill some big holes for a while as well. Got some scrap dynamat? Stick it on from the backside. There are all kinds of ways to get by.

Oh crap, I feel dumb. I forgot I had a roll of sound deadener in the toolbox...

[carguykeith]

I'd put the steel plugs with some fire-caulk or at least a piece of aluminum over the hole and then dynomat over it. Remember it's called a FIREwall for a reason....

[Vicinity]

I'd put the steel plugs with some fire-caulk or at least a piece of aluminum over the hole and then dynomat over it. Remember it's called a FIREwall for a reason....

You know what, that makes a lot of sense. I'll swing buy True Value sometime tomorrow afternoon and see what I can find.