904 question

Something isn't adding up. So I have the torque conveter that I thought/know I took out of the car originally sitting in the garage. I counted the splines and came up with 27. So either the transmission in the car was swapped before I got it AND I put the wrong torque converter, 18 spline, on (not likely, it never left the motor). Or I put the right torque converter, 27 spline, on and the transmission is original/older. I am 99.99% sure the 27 spline I have in the garage came off the cracked 318 I pulled from the car, but the kicker is that I could get it running enough before that it would move itself. Does anyone understand this logic, because I sure don't and I need some ideas.