This is me and my 1977 'Cheetah'. It had (I sold it in April 2000) a 160 hp O320,1 radio,
a Trimble 2000A GPS (no VOR!), Argus 3000 moving map, transponder, and a Telex Pro-Com 4 intercom.
It 'trues-out' about 140 Knots at just about all altitudes. (I've cleaned it up a bit) ;->