Do I need to just use OEM sending units and bushings to make them fit the bungs on the small block or is there another way?

Thats what I'm planning to do. Several companies have bushings from SAE to the metric sending units from your old engine. I'll likely also run water temp, oil pressure and volt meters in one of those 3 gauge pods from AutoMeter just to be absolutely sure the stock gauges aren't giving me goofy readings.

that's all i did.