EDIT Thank you for the information. It doesn’t look like I was lucky enough to have a ground lurking behind the outlet. Our breaker box is located approximately 40ft from the receptacle with a difficult to reach attic space (vaulted ceiling) between the two. I’m not aware of any 50amp capable grounds that could be tied into any closer. What would be a fair price for an electrician performing the work needed to get a 4-wire receptacle installed? Just looking for ballparks.
ORIGINAL We recently purchased a KFDD500ESS Dual Fuel Range which came with a 4 wire power cord. Our house was built back in the 70's, and we only have a 3 wire outlet. I'd like to remove the 4 wire power cord and install a 3 wire power cord, however I have a few concerns.
Based on my research, it looks like most ranges allow for this by allowing for a copper grounding strap that connects between the ground screw and the neutral terminal. However, the manual for this range doesn't say anything about it, and I do not see evidence of a grounding strap (which typically must be removed for a 4 wire configuration).
Would it be safe to take a thin length of copper and have it act as a grounding strap, connecting the ground screw to the neutral with the strap, then using a 3 wire cord? Similar to the grounding strap here: https://www.searspartsdirect.com/part-number/WB02T10067/0022/364.html
When it comes to the type of 3 wire cord, the manual states "This range is manufactured with a 4-wire power supply cord rated at 240 volts, 40 amps, rated at 194°F (90°C) and investigated for use with this range." Should I get a 3 wire cord rated for 40 amp or 50 amp? Is there a negative to getting one rated for 50 amp?
Here's some reference materials for the range, and some pictures: