Need a new distrbutor Kit? Help...

[oilsandsfj]

Im a little bit lost here. My FJ-40 has a 350 swapped into it by the previous owner. I remember him saying the block was from a 2000 chev. But Everywhere I go says Chev did not make a 350 that year (unless it was a crate?). There seems to be a lack of power, sputtering after 3000rpm and very unresponsive throttle. It seems to be an pretty inconsistent problem. I changed the fuel and air filter and cleaned the distributor as all the leads inside were pretty corroded. This seemed to fix the problem for a day. So to change the spark plugs and damaged one of the wires. I figured i'd replace the distributor and wiring all at once now. Only problem is i do not know what year the block is. How can i find out, what else do i need to know for ordering a new distributor and wires.