I used the complete serpentine system from the 98 that was the donor for my Vortec. No real problems. If you're using a stock-style hard fuel line with a mechanical pump, here's a post I wrote on how I did that:
https://67-72chevytrucks.com/vboard/....php?p=8823642
You'll need a reverse-rotation water pump (stock on the Vortec) and a reverse-rotation fan. The stock Vortec fan has a 19" diameter, and it won't fit in your fan shroud. I discovered that the fan from a 98 S10 4.3 liter is 17" and will just barely fit the shroud. I trimmed my a little for better clearance - I have about 1/4" all around.
My fan shroud was in pretty bad shape anyway, so I bought a new one from LMC. Then I cut it in half (top and bottom) and used joiner plates to put it back together. That makes it so you can actually access the fan without having to remove the radiator. I used an AC compressor from a 98, but an AC delete will work just as well. I also used the PS pump from the 98. If you remove the large fitting from the back of the pump, you can exchange it with the one from your previous pump, so the stock lines will work.
That's about it.