I have the conversion manual and the stock rear is retained (ditto on front and rear matches).
I have a 1957 truck, it had a 1970's rear. So I changed the ring and pinions on both the front and rear to 3:38 - Patrick's kits).
This allowed good highway cruising, but the 261 and later the 283 were OK, but not a lot of "punch." I now have a 348 with
3 deuces in it. Now it has a lot of "grunt."
don
