Wiring to Starter

[hdjpcp]

Greetings,
Would someone please tell me what wires should be connected to the starter/solenoid and at which posts on my 72 with 350/TH-400?
I have the positive cable from the battery to the center solenoid post along with a red wire, presumably ignition. I have a purple wire that comes to the left terminal of the solenoid (as you face the installed starter from the front of the car). A yellow wire with black markings comes off the right side of the solenoid. I have no ground from starter to ground.
The starter doesn't engage. I suspect something is missing, either a ground or something isn't connected where it should be. Lacking a wiring diagram, I'm hoping someone here can help.
Thanks.

 

[topless82vette]

any chevy Ive seen has the purple wire going to the terminal thats closest to the block, I think there is a S by this terminal I'm not sure about your other wire though

 

[barrier5]

purple to S,yellow to R,red and bat to B,try holding the key in the start pos. while moving the shifter through thr gears or try jumping the S and B terms.to see if starter will engage,you may have a bad switch,either park/neutral or the ign. switch at the bottom of the col.