I also made a new firewall for my aircraft following Beech drawing B17952. The firewalls used on the B17Ls before serial number 24 were a joke. They were aluminum and only covered the pilot's feet. There's nothing between the instrument panel and the rear of the engine. Also, the rear of the engine was open to the wheel well. After serial number 24 the oil tank was moved forward 3 or 4 inches to make room for a stainless steel fire wall between the oil tank and the instrument panel. I have talked to someone who flew serial number 3. They said it could get uncomfortably hot inside the cockpit. It did not help to have 5 gallons of hot oil just on the other side of the instrument panel. I also extended the firewall down to separate the engine compartment from the landing gear well, in accordance with drawing B17952.