Few ??'s for you guys. I'm doing a swap on a 84 c10. Motors an 04 4.8 (stock) with a th350 trans. What's needed to make the speedo gauge work with my ls harness? I was told some thing about a censor to adapt the the cable to my harnes but what ever they were saying didn't make any since Me seeing how the Cable goes to the trans and to the gauge. Why would I need an adaptor to make the gauge work? Will the trans shift ok as it should just hooking it up like it was from factory from back in the day?