ok just to make this real easy here.
drain coolant, disconnect thermostat to radiator hose, remove manifold to block hose, disconnect temperature sensor, disconnect fuel line from carburetor, dont have to disconnect alternator wires but it might make job easier to have wires out of the way.
remove at least one valve cover or manifold will hit on cover usually. disconnect throttle cable from carburetor, disconnect transmission kickdown from carburetor, if oyu ahve an older rc/td or truck wiot hcruise, remove cruise control cable from carburetor, remove brake booster vacuum hose, disconnect pcv hose, disconnect vacuum advance line from carburetor, disconnect coil, disconnect throttle return spring
this should be everything off of the manifold that needs disconnected.
if it is a dual plane manifold it will be easier to get the 4 center bolts with carb off of manifold, if not then leave carb on if oyu want.
take out 12 manifold bolts, being careful not to lose the throttle cable bracket and the return spring bracket.
using a small prybar or screwdriver, lift up one side of manifold to break it loose, lift off manifold, clean it up, install new gaskets on engine, place manifold on engine, starting at center of manifold and working your way out, alternating from front to back and side to side, tighten bolts to 35 lb/ft
reconnect everything, fill with coolant, start truck and enjoy
any further questions please feel free to ask
eric