I know nothing about Polarity Reversing Switches, but below are two entries from the 1947 and 1948 Chevrolet Service News periodical that were sent to repair shops. In 1947, Chevrolet said that mechanics should not wire around the switch; in 1948 Chevrolet explained what they had to change to eliminate the switch.

CSN 1947 October - Polarity Reversing Switch

Or, do a switch in this forum (The Electrical Bay).
Search on (type the following search "Keyword Search Terms": +polarity +reversing

CSN 1948 October - Polarity Reversing Switch

I suggest that you wait to see if anyone with first-hand experience posts information on how to remove the switch.

Or, do a search in this Forum (The Electrical Bay).
Search on "Keyword Search Terms": +polarity +reversing

Tim

Tim
1954Advance-Design.com
1954 3106 Carryall Suburban
1954 3104 5-window pickup w/Hydra-Matic
The 216 and early 235 engines are not "splash oilers" -- this is a splash oiler.