One thing to note about the inertia switch I linked: in the reviews, people note that you need to move a wire from the normally open to the normally closed contact. It is not difficult to do. I have done it to one of these that I purchased.

"...wire the car to use the ignition to power the relay coil and get a 78 oil pressure sender. Swap in a typical automotive relay..."

Any solution that bypasses the original relays. They have become a perpetual nuisance.

@SteveJ do you have a preferred place to connect the relay coil w/o cutting existing wiring?

I would have to look through the manuals to confirm. My wiring changed when I swapped over to EFI. Prior to that, I was just using the stock wiring.

You may have to back a wire or two out of a connector. At times like this, Vintage Connections can be your friend.