I was on cp performance web site shopping for new flame arrestors, mine are due for up grades. I found a billet arrestor from hardin marine that I like but it cost around
$400. Does anyone run this type of arrestor or know if there is any horse power to be gained over a stock arrestor?

No noticeable Hp to gained with a flame arrestor unless the one you have is too small to start with.

On this subject, I just put K&Ns on my old 502EFIs and found a valve cover breather hose just sitting there open. Should I put something on these boogers? Leave 'em alone? Route to intake? Or try one of these?