Found this website from another post here:
Multitudes of backtesting options here and much more. You can simply select about 20 different strategies (Permanent Portfolio is one) or input your own custom strategy/portfolio, set your rebalancing options, compare against other strategies and benchmarks.
PP is looking pretty solid , especially if you are at capital preservation mode. A PP custom version (no cash portion, rebalanced quarterly) actually beats Vanguard 500 over the past 20 years (barely, go back further and VFINX wins, but also with much bigger down years and max drawdown periods)