TreeFarm
Internet fabricator.
I'm glad that works for you! My 78 truck has a 79 cluster and It doesn't have the separate harness which is odd. But mine is a Frankenstein so the harness in mine may not be from 78. Them gauges look awesome, mind me asking what they set you back?
They weren't cheap, roughly $700 from summit after some discounts. About $100 cheaper than from Dakota themselves. The nice thing about them is they include an electric speedo drive to hook up to the trans, you can program the speedo from the cluster so no need for finding speedo gears when changing ratio or tire size. It will output speed to my ECM. So that solves one LS swap issue. They include the oil pressure and temp senders with standard and metric adapter bushings, another LS thing covered. They have tons of modern features like a service interval, hour meter and so on.