Answer to my own question...
1948 - Dewey
From 1860 to 1932 PA voted GOP every year except 1912 when it went for Teddy Roosevelt (P) rather than Taft (R) or Wilson (D).
* note I confused myself on Buchanan, of course he won in 1856 and being from PA of course he won his own state. Only Al Gore could lose his own state LOL...
Or McGovern, 1972