That's a pretty good size voodoo cam and I don't mean big like not street able but its not a mild type cam like the one I have in my 96 s10. Your gearing is just fine at 3.73 and building your turbo 350 with a shift kit will work well. You will need a good stall converter to get the most out of your cam. I have a 231/239 voodoo hydraulic roller in my 86 s10 and they are very good cams.
If you want to keep your current intake and I am assuming its the 86 and earlier intake bolt pattern? Vortec heads will not bolt up too the old style intake correctly and trying to make them do so is asking for trouble. I don't know how your current heads flow as I don't know much about the older heads and no some about vortec heads but just from reading on them from others on here.
For vortec heads to work with that cam you will have to most likely have the heads machined for the correct springs cause voodoo cams have very fast ramp rates and with high pressure springs they can rip pressed in studs out.
If you want to use your current heads you might look into a kit that allows you to have screw in rocker studs in place of your pressed ones and maybe someone on here can post I know there are some stock size springs that will allow over 500 plus lift and no machining will need to be done to your heads.
You might be able to make around 300 but with better flowing heads it will be much easier.