If the car is going to see a lot of street time I wouldn't use the 590 cam. It has no street manners,idles around 12-1500. The 557 would be better.IMO. You said tight budget get a valve job, check the valve springs replace if needed. Run those heads, use what you have. Headers if you can afford them. If you are startin from scratch things to consider. Ignition system, cooling system, a good drive line. Remember the key words "on a budget"