Speedometer Trouble

I have a '74 Dart Custom with an A904 trans. My speedometer is shot and the speedo repair guy says it's about a $200 fix. Well, just checking on-line I can get a set of nice looking Marshall gauges for about $350 (speedo + a tach & all the others I'd like to replace my dummy lites & not very informative gauges). However, ALL the new speedometers I found on-line are electronic requiring a "Hall-Effect Sender" unit. Here's the rub, EVERY picture of EVERY sender I can find shows a threaded connection while the connection from my cable to speedometer is a push-on with a side clip.

My question is for anyone with any experience with all this:
Can I get a new speedometer cable for my car that uses the threaded connection?
OR
Can I get a sender with the same connection as my old speedo?
OR
Do you have any other suggestions?

All I want is a functioning speedometer & odometer that will actually work with my car.