As contractions the difference between wouldja and woulda
is that wouldja is while woulda is (colloquial) would have.
wouldja
English
Contraction
(
en-cont)
* 2002 , Erich Segal, Love Story , HarperCollins, page 47:
- She screwed up her brow and frowned. "Oh Oliver, wouldja please?"
woulda
English
Contraction
(
en-cont)
(colloquial) Would have.
- You woulda told him the truth.
See also