Exhaust leak help

Hey guys,

I was playing around with the 318 today, getting her ready for the first test drive. I noticed a good amount of smoke coming out of the rear most corner of the headers (pictured below) on the passenger side. Its not a gaping leak but its a pretty steady little puff. The headers are very rusty and old looking. Is this a serious problem or just a little leak i can ignore until I get more time/money?

If its a major problem, what headers would go well on this motor? its a 318 w/ edelbrock streetmaster 318 mani and carter afb. Runs excellent otherwise.

D