Temperature Sending Unit

[70LonghornCST]

I recently purchased a new temperature sending unit and it was too big. I need one that has the flat head so I can connect my harness wire to it. My old one only had threads and a small nut. I don't want to cut the wire and crimp on a circular terminal. I want it to look stock with the plastic end that slips over the flat head. The one I purchased was advertised on eBay as "Temperature Sender 1967 68 69 70 71 72 Chevy/GMC Truck"

But when I pulled my old one out, it was much smaller. The new one required a 15/16" socket, while the old required a 3/4" socket. I pulled it from the side of the block on the driver side.

The engine is a replacement 350 crate engine from a GM dealer.

Help! Are there different sized temp sending units for a 350?