RE: Anyone got readings OS Fx 91?
Old well used 91FX (only one that ever ran good for me). Engine is on a Bruce Tharp Delta Vortex and it goes like a scalded cat with the 14x8
APC 14x8, 15% fuel, stock exhaust: 10410 rpms
APC 14x8, 20% fuel, stock exhaust: 10530 rpms