I just got done switching my switch out. Yes it was a b*** trying to put the cylinder back in, and never had an issue before. Sometimes you need to just play around with it. Look at the end of the cylinder and live it up with the inside of the switch. You'll see the square size goes from big on one end to small. And yes, make sure the hole next to the key hole is on the right side. Make sure you push the cylinder in with the cylinder being in acc location then turn it clock wise. There's a really helpful article in mustang monthly on it. Just google ignition switch and you'll see the article pop up with pictures. Very helpful.
2004 Nissan Titan Crew Cab
1966 Ford Mustang Original 289
Edelbrock RPM Performer Heads; bored .30 over
Weiand Stealth Intake, Holley 600 CFM Carb.
Comp Cam 268H 9.5:1 Speed Pro Pistons
Patriot Tri-Y Headers w/ 2.5" H Pipe, Flowmaster 40S
620 1" drop in front, CSRP Front Disk Brakes.
Ford 8 3.40 trac-loc rear end