c4 transmision

Looking for some input. We are putting a 87 model 302 in our 66 coupe, just had a 70 model c4 rebuilt to go in it. The problem is I don't know what torque converter to use I have a 26 spline input shaft and the bolt space on the flexplate is 11.5. Any help would be appreciated.

So my trans started acting up about 3 months ago. The transmission can't decide if it wants to be in 1st or 2nd gear when rolling slowly from idle to slight throttle. It shudders/ clunks back and forth from 1st-2nd. This would occur between 8-12 mph and usually on a slight incline. I took it...

Hey all thanks for looking at this. I have a 1969 c4 tranny in my 1966 pony. When it shifts from 2nd to 3rd gear if I am accelerating slowly it will slip into the 3rd gear (my engine will rev a little high until it gets into gear). If I am accelerating at a nice moderate speed it will go into...