X2 on every thing Andy said. If you have the donner truck, you could take everything from it, but the 98 has OBD II ECM running the engine management systems. You ether need to use the ECM from the 98, along with all the wiring, or swap it over to carb as Andy said. You can feed the carb with an electric fuel pump, and you will also need a HEI distributor, that you can swap from your truck. It only takes about 12 PSi of fuel pressure to run a carb I think, but the 98 takes just over 60 PSI and the fuel pump is in the fuel tank on the 98. You could use that fuel pump, and tank on your truck, but you will need a fuel pressure regulator to drop the fuel pressure to IDK 12 to 14 PSI maybe.