The subject says what I would like to do, here are the details:

I have a 512ke with the MacRescue upgrade board that makes it the
equivalent of a Plus (System 7 and MacEnvy both identify it as such).

The MacRescue board clips onto the 68000 on the MB.  It also has
a 68000 itself.  Periodically I have to remove the clip (not an
entirely easy thing to do) and clean the "legs" of the 68000.
Larry Pina's book asserts that this is occasionally a problem with
snap on upgrades:  the 68000's "legs" will oxidize, causing 
unusual system errors.

Well, that's me.

So, I would like to do something permanent, and I think it would be
fairly easy to put a socket in where the 68000 currently is, and
modify the MacRescue board to plug in.  What I'm not 100% sure of
is whether it will work.  It seems to me that the two 68000s aren't
acting independently; so removing one shouldn't have any effect on
the performance of my Mac.  I'm about 97% sure.

Will someone provide the extra 3%?