What to do
As for cost, it's hard to give an estimate if you're planning to do various upgrades along the way. You could easily spend thousands more than would be required for a simple "refresh". There are a ton of "might-as-wells" and plenty of supporting modifications to be considered if you want to upgrade the cam. You'd really need to come up with a list of items you want, or a power range that you're looking to achieve, and then start looking at prices for the sort of parts you need/want to meet your goals. If you're doing the labor yourself it will save a bunch, but many of the parts are not cheap and, again, there are countless upgrades that "make sense" to do if you want to add a cam and make more power.
Maybe headers and new exhaust? If it runs good maybe run a compression check to confirm its firing on all cylinders.










