1970 c20 drum to disk alignment question

[paulbrgr9999]

My 70 c20 is getting disk brakes next week. The doner is a 72 c20.

1. How far can I drive the truck without an alignment?

2. When the alignment is done do I use the alignment spec for a 72 or a 70?

The repair manual I have states that the toe in for 70 should be*
1/8-1/4. For 72 it states exactly 3/16.*



thanks,

paul