489 vs 742

[Derrick Brown <63max426@xxxxxxxxx>]

hi all,

center section questions.
ive got a completely rebuilt 489 cased suregrip (bearings , ring/ 
pinion and suregrip) with new 3.55s in it.

I want to swap to a steeper gear (likely 4.10, 3.91 minimum I think)  
since im  running a tall tire.
I still have my 742 case.
"IF" i want to get a new 4.10 ring/pinion for the 742 case ( i think  
all ill need is a shim kit for the pinion gear).  Will my large yoke  
and all the new bearings , suregrip and carrier(from 489)  all swap  
over to the older style case?
It is my understanding that the only difference is the ring/pinion  
with shims (742)  versus ring/pinion crush collar (489)

True or false, and what am I missing?

thanks,


Derrick Brown
'63 Sport Fury, 4 speed
derrickb@xxxxxxx