Hard to tell from the pic being close up, but I got a GPS speedo that I've used in the past for my other toys and it seemed to fit into the hole after a bit of filing away some plastic. If you already have a hot wire under the hood (which you should somewhere) it makes it much easier. Also, if you have other gauges on the hood you can see if there is a harness that isn't connected, test it with a multimeter and tap into those wires. Been working like a charm on my 97 Challenger!
Best,
Jake