Try Advance Adapters website. They should have the parts you need for this swap.
.045"
All V8 Chevy plug gaps in 1977 was factory .045
ac delco plug r45stx is a good plug for all 350 olds eng. w/hei gap is set at .60 thousands do to the hotter heat range
A/C plug # R45TS and it gaps at 0.045 That is the factory plug.
1-3-5-7- 2-4-6-8
The frame engine mounts need to be moved and the headers need to swaed with the 350.
1 8 4 3 6 5 7 2
That car didn't come with a 350. The V8 available for that Monte Carlo was the 305 which took the ACDelco R43TS spark plug.
Need to know the year. You will need to ask your question again with that info.
Need to know what year it is to answer correctly
air, fuel, and spark is all you need.