if you go with the vortec heads, you'll also need to get center bolt valve covers in addition to the dedicated intake manifold. If you go with a cam that has some lift to it, you may also want to have the heads machined for screw in studs, and matched valve springs are always a good idea. There are some hidden costs basically...
They are a good head though, and if you're going with a mild-mannered combo on the street as you describe, the heads will probably be a good deal for you.
Check out Sallee Chevrolet, or Scoggin Dickey Performance Chevy for a full kit that includes the heads with all the gaskets, intake, valve covers, and self-aligning rockers that you'll need (if you don't have them already). The kit comes out to around $700 last time I looked.
As for a cam, Something with less than 220 degrees duration @.050'' lift is a good choice. The Vortec head's don't have the best exhaust port, so a dual patterned cam may be beneficial. Something like the Comp XE262, or XE256.
Another thing you'll need to consider when swapping the heads is the compression ratio change. If you have old 76cc chamber heads, the vortecs have 64cc chambers which will boost your compression quite a bit.
Just a rough guess... I'd say a swap to the Vortec heads would probably be worth 30+ horses over some old 882 castings. With the Comp XE262 cam, 350 horses wouldn't be impossible.
You may want to look back at an old article they had in Chevy High Performance Magazine about the Vortec heads... With the XE268 cam they managed to get 400 horses out of their test 350.
- '68 Chevy Camaro (sort of done, but always subject to improvement)
- '63 Pontiac Tempest (work in progress)
- '72 Datsun 240-Z (back-burner for now)