GMC LT-9 Help please

[Franky Dump Truck]

I've got a 1986 GMC K3500 dump truck with an LT-9 350. It supposedly makes 160HP but I kind of doubt it. I'd like to make some more power to make the truck more usable. It doesn't seem to have a lot of power with a load on. I'm thinking of the following:

1. Long tube headers to twin mufflers

2. Edelbrock Torker intake manifold and holley 650 carb

3. An "RV" cam that makes good low end torque.

Does any one have any suggestions on the cam specs? Has anyone done anything similar? Anything that I haven't thought of?

Thanks in advance for any suggestions.