Was it common for Democrats to vote Ford in 1976?

[Sumner 1868]

I believe Jimmy Carter was actually more anti abortion than Gerald Ford was.

Privately? Possibly. However, the Democratic 1976 platform opposed a constitutional amendment on the subject while the Republican platform supported one (albeit with some language acknowledging their was disagreement within the party on the subject).

http://www.presidency.ucsb.edu/ws/?pid=25843
http://www.presidency.ucsb.edu/ws/index.php?pid=29606

Both Carter and Ford stated they supported their party platforms on the subject in the third presidential debate on October 22nd.

http://www.debates.org/index.php?page=october-22-1976-debate-transcript

So the partisan divide was already present, just in a far milder tone.