I have a k&n air filter off my truck. Can I put it on my 350 mag or is it special becuase it is a marine application??

You need a Coast Guard approved flame arrestor. But that only REALLY matters if your boat explodes.
BTW, K&N makes flame arrestors.
Gary

call k&n customer service (not sure of the number check there web site) because alot of there fliters are cost guard approved they can tell you if yours is from the part # on it.

If its a FLAME ARRESTOR it will have a U.S.C.G. # on it. It will read something like USCG#xxxxxxxxxx

Also DON'T USE A REGULAR AIR CLEANER!!!!! One backfire and the paper element might catch on fire and you would never know it till it was too late.......

BH