The idle value will be different in gear vs. out of gear and ATX vs. MTX.
At fully warmed up and heat soaked our SPI ATX:
- in gear averages 650 rpm
- out of gear averages 700 rmp
Member of the Dropped Valve Seat Club.
Replaced #4 Piston, Rings, Rod+Bearings, AERA Re-Manufactured Cylinder Head and a light Hone. Then CLEANED the hell out of everything.