[FC] Transmission woes

[Charles M. Wrobel]

I had a problem with the differential (389) in my 63
Corvan (with 4 speed) and took it to our local Corvair
mechanic who located a replacement (327) with a
fourspeed attached to it that seemed fine. The complete
unit was installed. Right away there were some problems
with the new transmission and eventually (in less than a
month) the whole transmission failed. I never had a
problem with the old transmission and I'm wondering if
maybe it should be put back in there. The mechanic is
thinking we should fix the newer transmission so that we
can stay with the larger shaft.

What's the general opinion out there regarding the input
(?) shaft. Is it that essential to have the later,
heavier duty one or can you get by with the smaller one?
I realize they are not directly interchangeable.

My automotive knowledge is limited so please excuse my
ignorance and use small words if you are kind enough to
answer.

thanks,

Charles

PS - on a positive note, the 327 diff is fantastic with
my 110. It feels like about 10HP boost or something, I
can't imagine going back to the 389's