Base engine: Chevrolet Performance #10067353
http://www.summitracing.com/parts/nal-10067353
Manifold: Some choices here, but Edelbrock 2101 works well.
http://www.summitracing.com/parts/edl-2101
Headers: For a C truck, Hooker 2452 fits. For a K truck, Hooker 2453 fits.
http://www.summitracing.com/parts/hok-2452hkr
http://www.summitracing.com/parts/hok-2453hkr
Cam: Lots of choices. You can download Comp Cams Camquest software (just google Camquest) and try them out. Some popular ones:
12-300-4: 275 hp at 4000 rpm, 422 lbft of torque at 2500 rpm, 320 lbft at 1000.
This is what I am running. Lots of torque out of the hole, and beats almost any cam in this engine with the stock heads up to 3500 rpm or so. Perfect for my driving, but some people want more up top. Stock lift, so no need to change springs, and no need to change lifters if you change the cam without ever running the engine. Run the engine 10 minutes, and you have to change the lifters when you change the cam, because they take a set to each other very quickly.
12-235-4, 12-234-2, 12-211-2 are all worth looking at, depending on what you want. Most give more hp than the 12-300-4 by virtue of winding tighter on top. Some have enough higher lift to need better springs. Look at the Comp Cams page for each to see the Notes section; it will tell you if you need the springs. These give in the 290-310 hp, 400-420 lbft range, with the torque coming on low enough to get a truck moving.
Run them through Camquest and see what you like. Here are the engine parameters you need to enter for this engine. Setup down the left side is:
Usage 3, 4, or 5
Hydraulic
4500 lb vehicle weight
Carbs
Chevy 350
2-valve, wedge, low perf/stock ports_valves
1.940 in
1.500 in
8.50
Dual plane high flow
600 cfm
None
Gasoline
Large tube headers, mufflers without cats
When you run simulations, make sure you give due deference to the torque curve from 1500 rpm to 3500 rpm. Wind-up horsepower is nice, but you have to get the truck moving first.