To get to the 600 grain range, you'll need to add a 100 grain brass insert, probably a 75-125 grain adaptor and a head in the 125-150 grain range. Of course, can play with the head and adaptor weights. May need to go to a 250 with that kind of weight up front.
A high FOC 600 grain arrow with a two-blade head will be good medicine for moose.
I'd recommend more bow weight if you can handle it. Of course, you can kill a moose with a 50# bow, as I'm sure others will point out. But they're big critters, with thick,tough hair, hide and ribs, and the more punch you can muster, the better. Good luck. Moose are fun, and big!