1974 Valiant Scamp, timing retarding when revved

Yessir, I read over it. What I'm having trouble translating over the the edelbrock between your directions and the manual are these two steps "2)With the Curb-idle screw,set the t-port exposure under the butterflies,to about square to rectangular,or .025/.030 high. 3)Set the idle-speed with bypass-air,and idle-timing."

2) I read this, and your response to another member with a similar issue. This sounds like I want to close the butterflies with the idle screw JUST to the point where vacuum to the timed port dies off? I'm not sure how the .025/.030 measurement is used in relation to the t-port exposure. Should I pull the carb off the intake and set it using a feeler gauge?

3) This sounds like once the t-port is set in step two, I would get my idle speed set at the 750RPM spec using only the air the butterflys allow past them, adjusting the idle mix screws, and timing to get it in spec and smoothed out?

Sorry if I seem dense or stubborn, this is only the 3rd REAL carb'd vehicle I've had, and second Edelbrock. Never had such strange issues on the Pontiac 400, but this particular car has had a lot of very shady work done to it while the previous owner had it. Just trying to understand it and reverse engineer it all.