Well, if the steering wheel doesn't lock your doing great, but if so, you must snap the wheel real hard one way to bend the stop plate. Then if you go to the base of the column, there is an ignition module, if you take the screws out of it, you can use a screwdriver to pust the button down in the module and start it.
1975 for the HEI (High Energy Ignition) system (no more ignition points)
most older trucks can be started without a key
just do what i did and take out the tumblers that the key slides over.
check the oil
2007
By turning the ignition key...
Coil
replace module, rotor button and dist. cap
how to start a 1993 chevy tahoe without a key
remove the ignition tumbler from column and crank it with a insulated handle flatblade screwdriver if the ignition is located in the dash remove key tumbler by inserting a small pin in the hole located above the key hole and it will pop out using a screwdriver and turn it over that way
Replace the engine coolant sensor.
I hav just purchased a 58 Chevy apache and are having the same problem. I did find a site that displays a complete diagraham for the entire ststem includingthe ignition switch. The site is http://www.classicchevytrucks.20m.com/cgi-binwiring.jpg Good luck with the changeover wspringerjr@yahoo.com