AL 3 speed trans part NEEDED BADLY!!!

[GMCNUT]

Hey guys - boy I sure hope one of you can help me here; I carried my 1961 Chevy Apache 3/4 ton pickup to my buddy's house this week to get him to help me install a new clutch; we were surprised to find that it took a 11" clutch instead of the standard 10" but then the bomb: the pictures show a part (do not know what its called) where the throwout bearing is supposed to ride and mine has the whole shaft broke off so we are completely dead in the water until I can locate a replacement! I went to a buddies house and he gave me one off a 1969 3 sp trans (the one on the left in the picture) but it is larger diameter than mine. My broken one is exactly 4 and 5/8" across where the one off the 69 is more like 5" or bigger - so it will not work to replace mine.

I do not know enough about the 3 speed transmissions used in 60-66 to say at what point a trans would have the larger version, but if anyone can produce an exact match to mine and sell it to me you can pretty much name your price because I am sort of hung up here without one....AS ALWAYS ANY HELP FROM YOU GUYS IS GREATLY APPRECIATED!!!