Because there is so much advice being thrown in here, I would like to add my two cents.
I would put in some headers and a 2' exhaust, get a better ratio rear end and drop in a cam, intake and SMALL 4 barrel carb. You can make a screamer out of a 283 with 350 CFM two barrel. 600 cfm is just bordering on too big for a 283 to be a good streetable driver. Big is for strip, small is for street.
Make sure that the brakes and front steering are in "excellent" working order first.
