Likely electoral map:
Reagan would even in 1976 have been able to challenge Carter in the south, especially with the opposition of the ticket to gun control - Louisiana and Mississippi might well have been closer than in any actual election (and remember that in MS Carter's two actual elections are the two closest on record). Although I am not sure if Reagan would have not been too extreme to hold Oregon and Washington, and doubt that with the economy as it was in 1976 he could have held Maine given that it was the poorest state (adjusting for cost of living) in the Union and would have feared his economic policies of a free-market Republican like Reagan (although the Pine Tree State did reject Mondale and dukakis quite firmly in 1984 and 1988)