Okay im wanting to swap in a c-4 into 66 289. It has the 6 bolt bell housing pattern. Can i use a 70's and later model c-4 with a special torque converter. I was thinking about getting one from summit but it has the 26 spline input shaft. If so where can i get the torque converter. Also what bellhousing will i need. Or would it just be better to find a c-4 from a 65-69. I have looked for info a long while on this and any help would be appreciated.