Whats a good body filler???

Hey whats a good body filler that will have no affect to heat? I need something durable, im about to fill in my firewall and floor, and just looking for some opinions.

lead

there is no bodyfiller immune to REALLY extreme temps, but it does get pretty hot when curing. evercoat gold is all i use w/ the lil fiberglass resin mixed in.

metal to metal or lab metal may hold up pretty good in EXTREME heat.

Where can u get lead?

not sure about extrememe temps, but i used rage on my firewall and a year later never ever had one problem, knock on wood

RAGE for sure

rage is good.

And nobody really uses lead anymore, because it causes cancer.

rage is awesome..its alot easier to work.....but I've used evercoat lightweight for years with no problems..

eastwood sells lead and a lead free style led solder.