A big block 454 engine was available that year so yes it will fit.
Pretty much any 454 will fit but stay with a carbed motor with HEI ignition (unless you want EFI). The bellhousings are the same, the tranny will bolt-up but if you have an auto I would upgrade to a TH400. If you stay with the HEI distributor it will connect to your truck, wiring will be the same. You may have to swap sensors (temp, pressure, etc the sending units for a gauge verses a light are different). Throttle cables and kick down (or T/V on 700r4) brackets should swap. Check the exhaust manifolds. May have to change your exhaust. Cooling. The 454 should have a beefier rad over the 305/350. Engine mounts check. Might have missed a few small things but that should be the main things. It is always best to do a swap from a donor vehicle that will have all the parts you need.
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