1974 Spider with SPICA running grossly rich. Depth of depravity inflicted by PO(s) on virtually every system yet to be plumbed. Obtained proper tool for locking ring on the fuel cutoff solenoid and it won't turn. Basting for past week in PB Blaster; occasional tapping with as much force as I dared. Still won't move even with additional leverage from vise grips clamped to the tool's lower prongs. Due to proximity of TA, I'm leery of putting a torch down there. But I suppose I could take the TA off (time to test it anyway), and then apply heat. Any suggestions?