The 1947 - Present Chevrolet & GMC Truck Message Board Network

Ive been getting a stumble on power at average speeds, gets real noticeable on pulling hills and heavy demands, I can sometimes feel the light, knock,knock,knock,knock on the driver side cylinders through floor, only does now and then, can still ride to highway speeds, and normal acceleration, just feels kinda ruff when it does and lacks power. Ive changed plugs, wires, distr cap, though some of the wires are different from replacing burnt ones but same mm. Should i check timing, a while back i had to re tap rocker arm on # 6 cylinder, and had a bad wire on # 3 for a while until I noticed it. This is the original 5.7 pushing maybe 200K and some plus. In the future im thinking of going after some head work to gain alot of power back, but need advice on where to start for now??? All the basics of tuning, ignition, top end maintenance, carb, etc. I would like to find a good book with most of the info other than basic manuals, im on youtube mostly and a lot of things are left out on videos.