Even though this is a Devoted Democrat thread, I might as well make a serious response:
No, I doubt it. The trend was just too anti-Republican. At best I see Reagan helping Ford increase his showing among the Interior and Great Plains conservatives, but not much elsewhere:
Probably the biggest difference would be Texas, with Reagan's pull among the rich oilmen and the like. In real life it was a pretty close Carter victory, but I believe that Reagan probably was considered a pretty popular figure in the state (he won the TX Primary with 66% of the vote) who could make the difference. Really though, many of these states are up for debate. Sure, the Interior West would've been safe Republican, but other than that I see most of these states going either/or. I believe the South would've still pulled for Carter, due to homeboy effect, but some of the more "business friendly" states might've pulled for Ford with Reagan on the ticket. THough Reagan's conservatism turns some off, I don't see Vermont and Maine pulling the switch for James Carter.
It's very hard to predict how an alternate 1976 would look, because again the political environment of the times.
