Got a hole in the firewall from removing your factory a/c evaporator core or heater box on your 1973-1987 Squarebody C/K pickup truck? Detroit Speed has a bolt-in solution that doesn't require any welding. If you have installed an aftermarket air conditioning system and no longer need your factory a/c evaporator core or stock heater box, this stamped 18-gauge mild steel cover bolts right in place using the original factory hardware. Once painted to match your firewall it delivers a clean almost factory like appearance without having to custom make a panel and then welding and grinding to make it pretty. Plus, it's made in the USA. Installation tip: Use strip caulk or similar to seal the plate against the firewall.