overbet push from terrible player

[tommo]

player is like 50/30 and seems to be quite overaggressive. I haven't seen him play too many hands but he's definitely spewing.

I have 6[img]/images/graemlins/club.gif[/img]7[img]/images/graemlins/club.gif[/img] in the button. all fold to him he raises 3xbb, I call.

effective stacks $600

flop (3[img]/images/graemlins/diamond.gif[/img]4[img]/images/graemlins/club.gif[/img]J[img]/images/graemlins/spade.gif[/img]) $100 in pot
he bets $50, I call

(figuring I've got implied odds for a backdoor flush draw or hitting my gut shot, and I might just float him)

turn (6[img]/images/graemlins/diamond.gif[/img]) $200 in pot
he goes all in ($500), I??

can a good argument be made for calling here? or is it just spew?

Edit: we actually do have some history here. I was running over him earlier in the day. Not sure if he realizes that I'm the same person he was playing then though