So in 20+ years I'm actually following the manual to tune my 400 bird. The mixture screws are common sense and I've always used a vacuum gauge with a RPM gauge to set them just right. Now, the idle speeds are somewhat strange....My car has A/C so I do have the solenoid. I warmed up the car and adjusted the hex on the solenoid to get 650 RPM (with the tranny in Drive). wow it must be in Drive! Then I disconnected the solenoid and adjusted the carb idle speed screw to get to 500 RPM..still in "Drive". Then I set the fast idle to 2500RPM!!! as stated. Wow! These speeds seem really high especially the fast idle. I don't think I ever heard a car doing 2500 RPM at start up, and the regular idle being at 650RPM in Drive is idling at almost 800RPM in neutral now. What do you guys think? Is that were you have your speeds set at? BTW: Timing set with vacuum hose and solenoid disconnected.