I have suggested that my customers (who have purchased the later model dashes
from me) hook the lead from their oil pressure sender directly into pin
number 4 (see Bentley picture of the printed circuit in the section about
testing the dual oil pressure sender setup).  That way on the older vans that
don't have the dual senders your single sender will work the same as it
always did (with on worries about wether it is above or below 2k rpms).  I
would remove the "L" board and put it on your coffee table as a conversation
piece or sell it to a list member who has a bad one.

I provide wiring diagrams and "helpful hints" sheets in with all of the tach
setups I sell ($100 plus shipping for List members).

Thanks,
Ken Wilford
http://www.vanagain.com
John 3:16
Office (856)-765-1583
Shop (856)-327-0027
Fax   (856)-327-2242