90-91 1/2 trarnny?

i heard today that in the middle of 91 honda changed the tranny in the 91’s to the 92-39 tranny. is this true. if so, how can i determine what clutch to buy?

I have never heard it before. Just buy the 90-91 clutch set and you will be good to go.

The only other way to make sure is to either open the tranny up and check out the internals or count the teeth on the input shaft, which is much easier than opening up the casing.