I spent a good two hours last night trying to get a used 11" converter to go on to a used BB 727. I put a new seal in the front pump, line the pump drive so its top and bottom, held the converter so that hub notches were top and bottom, and then spun it back and forth trying to get everything to line up and the converter spline up correctly.
any tricks?

What year transmission and converter ? 66 and back used a different spline count than 67 up.

both fine spline early 70s.

somtimes you have to lift it up and down while you just barley turn it side to side.it helps ALOT if the trans is held vertical.is it in the vehicle?

I get the grooves/notches to line up side to side or top to bottom just like you did then insert it with maybe a slight back & forth rotation so my alignment is dead on. I'd think spinning it would move the notches/grooves out of clocking alignment.

Slowly spinning the converter with a slight in/out motion has always worked best for me (it helps to hold your tongue just right)

In worst case scenarios you can turn the trans up and rest it on the tailahaft and drop the converter in vertically using a couple of long bolts in two drive lugs. When correctly installed the drive lugs will be at least 1/2" in from the bellhousing face.

day two, I went and got some pieces out of another 727 and stuck them in the converter and they line up perfect, I called the owner and he said when he pulled the engine, he didn't unbolt the converter from the flex-plate, but rather left it hanging from the back of the motor. I also took your advice and unbolted the tranny and stood it on the tail-shaft, and it still doesn't spline into the pump.

If the previous owner took it apart like that, maybe
he boogered up one or both of the splines enough so you are having
problems.

Not easy to get at the converter splines, but take a close look at
the trans shaft with a magnifier and see if there is any distortion.

Splines are necessarily a tight fit and any marring or burrs are
going to be a problem. A mill file may correct it.

Joe

i cant imagine doing that with out some kind of damage,check to make shure the snout is not BENT.

I've left many converters in the tranny when removing the motor in many different cars, I've never had or heard of that causing a problem I always push the converter back into the tranny as far as it can go before unbolting and removing the motor. Same deal on removing the tranny, disconnect the converter and slide it all the way back, remove the tranny and go from there

That is the problem, he didn't leave the converter in the tranny, but rather left it hanging off the end of the engine. Now I can only get the converter to spline onto the input shaft and sometimes it gets stuck at that(hard to pull back off).

I bet the converter splines are fubared inside from what he did. You wouldn't happen to have another converter handy for a quick trial fit would you?

yes I do, but I am just going to take it to the tranny shop and let them deal with it. I will let you all know what I find our.
thanks Moparts

well the results are in, someone changed out the input shaft by putting a 19 spline in place of the 24 spline.