Gun Parts lists the old style firing pins.
Part number 39A-32:
http://www.gunpartscorp.com/Manufact...037.htm?page=2
Poppert's list parts, contact them:
http://www.poppertsgunparts.com/cgi-...a_gunparts.cgi
Bob's Gun Shop lists old model firing pins. Contact for details:
http://www.gun-parts.com/marlin/
Wisner's has a section on Marlin firing pin designs that might be useful:
http://www.wisnersinc.com/additional...22leverFP.html