Aftermarket gauges

Son2PopsCuda said
Hope all is well with everyone first and foremost. So I purchased a set of gauges, not to look cool so I’m hoping I can get them going. The gauges are the typical water temp, oil pressure and volts. The volts are by far the easiest, the water temp easily figured out (hope I didn’t speak too soon) but the dreaded oil pressure has me stumped, can someone please help me figure this thing out. The motor is the original 273 with original manifold and original radiator. Any help would be greatly appreciated. Thanks is advance

I also don’t know what this is, I had the carburetor line hooked up to for vacuum as it does idle better but I honestly don’t think it’s for that. I circled the part in the pic and the part in question is located on the backside of the manifold on the driver side very close to the distributor.