I would like to convert this unit to Propane (Kenmore cook top 911.32385890). I know I need to change the orifice. How many are required? Are there any other parts that require changing?

L.P. conversion kits are always shipped with the unit. The LP orifice is nickel and has notches on the points of hex nut. On the oven you turn the orifice hoods clockwise 2 1/2 turns. On the regulator you remove and reverse the cap so that "LP" faces up, raising spring tension, since LP gas is higher pressure that natural gas. You may look at this manual which is basically the same for your unit:http://dl.dropbox.com/u/8010163/Whirlpool_Oven_Manual.pdf The orifice is usually in a plastic bag with your manual taped to rear of unit.