On Sun, 21 Apr 2013 15:21:32 -0700, Ashton Crusher
wrote:

I was thinking of putting a higher pressure cap on one of my cars to
increase the factor of safety against boiling.


How often does that happen? If it is frequent, you have other
problems that need to be fixed. Last time I had a boil over was
probably in the 1960's or so.

This is not the proper thing to do. The engineers have put a lot of
work into getting the right temperature and pressures and you think
you can do a better job? Really?