Was draining my '70 CL350's tank today for removal. Was surprised to find about 1/3 gallon of fuel left in the tank after draining with petcock set to reserve. No sediment or clog... Anyone out there know if that '70 tank took a specific/oddball petcock? I used a K&L 18-4150, which was at least advertised as the correct one, but I've been burned by "fits multiple models and years" before.